Face Selectivity of the Diels-Alder Additions of 2-Substituted 5,6-bis((E)-chloromethylidene)bicyclo[2.2.2]octanes

The preparation of 5,6-bis((E)-chlorommethylidene)bicyclo[2.2.2]oct-2-ene ( 13 ), 2,3-bis((E)-chloromethyl idene)-5exo,6exo- and -5endo,6endo-epoxybicyclo[2.2.2] octane ( 14 and 15 ), 5,6-bis((E)-chloromethylidene)-2exo- and -2endo-bicyclo[2.2.2] octanol ( 16 and 17 ) and 5,6-bis((E)-chloromethylidene)-2-bicyclo[2.2.2]octanone ( 18 ) are described. The face selectivity (endo-face vs. exo-face attack onto the exo-cyclic diene) of their cycloadditions to tetracyanoethylene has been determined in benzene at 20°. It is 78/22, 80/20, 60/40, 68/32, 3/97 and 30/70 for 13 , 14 , 15 , 16 , 17 and 18 , respectively.     

Face Selectivity of the Diels-Alder Additions of Sulfur-Substituted Dienes and Tetraenes Grafted onto 7-Oxabicyclo[2.2.1]heptanes

Stereoselective synthesis of 2-methylidene-3-[(Z)-(2-nitrophenylsulfenyl)methylidene]-7-oxabicyclo[2.2.1]-heptane ( 16 ), 1,4-epoxy-1,2,3,4-tetrahydro-5,8-dimethoxy-2-methylidene-3-[(Z)-(2-nitrophenylsulfenyl)methylidene]anthracene ( 18 ), and 1,4-epoxy-1,2,3,4-tetrahydro-5,8-dimethyoxy-2-methylidene-3-[(Z)-(phenylsulfenyl)-methylidene]anthracene ( 19 ) are presented. The Diels-Alder additions of these S-substituted dienes and those of 2,5-dimethylidene-3,6-bis{[(Z)-(2-nitrophenyl)sulfenyl]methylidene}-7-oxabicyclo[2.2.1]heptane ( 17 ) have been found to be face selective and ‘ortho’ regiospecific. The face selectivity depends on the nature of the dienophile. It is exo-face selective with bulky dienophiles such as ethylene-tetracarbonitrile (TCNE) and 2-nitro-1-butene and endo-face selective with methyl vinyl ketone, methyl acrylate, and 3-butyn-2-one. In the presence of a Lewis acid, the face selectivity of the Diels-Alder reaction can be reversed. The addition of the first equivalent of a dienophile to tetraene 17 is at least 100 times faster than the addition of the second equivalent of the same dienophile to the corresponding mono-adduct. The X-ray structure of the crystalline bis-adduct 43 , a 7-oxabicyclo[2.2.1]hepta-2,5-diene system annellated to two cyclohexene rings, resulting from the successive additions of methyl acrylate and methyl vinyl ketone to tetraene 17 is presented. Only one of the two endocyclic double bonds of the 7-oxabicyclo[2.2.1]hepta-2,5-diene deviates from planarity, the substituents bending towards the endo face by 5.7°.     

Synthesis of new heterocycles by oxidation of functionalized cyclic derivatives of bis(2-chlorovinyl) sulfide and selenide

Oxidation of 4-substituted 2,6-bis[(E)-chloromethylidene]thiomorpholine with hydrogen peroxide in a mixture of chloroform with acetic acid afforded the corresponding 4-R-2,6-bis[(E)-chloromethylidene]-thiomorpholine 1-oxide. The results of oxidation of bis[(E)-chloromethylidene]-1,4-dichalcogenanes under analogous conditions depended on the chalcogen nature and its position in the ring. The reaction of 2,6-bis[(E)-chloromethylidene]-1,4-dithiane gave 2,6-bis[(E)-chloromethylidene]-1,4-dithiane-1,1,4,4-tetraone, whereas 3,5-bis[(E)-chloromethylidene]-1,4-thiaselenane-1,1-dione was unexpectedly obtained from 3,5-bis[(E)-chloromethylidene]-1,4-thiaselenane. 2,6-Bis[(E)-chloromethylidene]-1,4-thiaselenane and 2,6-bis[(E)-chloromethylidene]-1,4-diselenane decomposed under the oxidation conditions.     

Face Selectivity of the Diels-Alder Reaction of 5,6-Bis((D)methylidene)-2-bicyclo[2.2.2]octene

The face selectivity (endo-face vs. exo-face attack onto the exocyclic s-cis-butadiene moiety) of the [4+2]cycloadditions of 5,6-bis((D)methylidene)-2-bicyclo-[2.2.2]octene ( 11 ) to strong dienophiles has been determined in benzene at 25°. It is ca. 95/5, 75/5, 70/30, 60/40 and 50/50 for N-phenyltriazolinedione (NPTAD), tetracyanoethylene (TCE), dimethyl acetylenedicarboxylate (DMAD), maleic anhydride (MA) and singlet oxygen (¹O₂), respectively. The endo-face preference is probably due to a participation of the homoconjugated double bond at C(2), C(3) which makes the etheno bridge more polarizable than the ethano bridge in 11. The absence of face selectivity with ¹O₂ is consistent with an entropy-controlled mechanism involving the intermediacy of an exciplex.     

Face selectivity of the Diels-Alder additions and cheletropic additions of sulfur dioxide to 2- vinyl-7-oxabicyclo[2.2.1]hept-2-ene derivatives

Racemic 6-ethenyl-7-oxabicyclo[2.2.1]hept-5-en-2-one ( 23 ), 5-ethenyl-7-oxabicyclo[2.2.1]hept-5-en-2-one ( 25 ) and their ethylene acetals 24 and 26 , respectively, were derived from the Diels-Alder adduct of furan to 1-cyanovinyl acetate ( 27 ). The Diels-Alder additions of 26 to dimethyl acetylenedicarboxylate, to methyl propynoate, to N-phenylmaleimide, and to methyl acrylate were highly exo-face selective, as were the cycloadditions of methyl propynoate to dienones 23 and 25 and of dimethyl acetylenedicarboxylate to ethylenedioxy-diene 24 . The cheletropic additions of SO₂ to 23 – 26 gave exclusively the corresponding sulfolenes 57 – 60 resulting from the exo-face attack of the semicyclic dienes under conditions of kinetic and thermodynamic control.     

Synthesis of (+)-1,3:2,5-dianhydroviburnitol ((+)-(1R,2R,3S,5R,6S)-4,7-dioxatricyclo[3.2.1.03,6]octan-2-ol)

Epoxidation of (?)-(1R,2R,4R)-2-endo-cyano-7-oxabicyclo[2.2.1]hept-5-en-2-exo-yl acetate ((?)-5) followed by saponification afforded (+)-(1R,4R,5R,6R)-5,6-exo-epoxy-7-oxabicyclo[2.2.1]heptan-2-one ((+)-7). Reduction of (+)-7 with diisobutylaluminium hydride (DIBAH) gave (+)-1,3:2,5-dianhydroviburnitol ( = (+)-(1R,2R,3S,4R,6S)-4,7-dioxatricyclo[3.2.1.0^3,6]octan-2-ol; (+)-3). Hydride reductions of (±)-7 were less exo-face selective than reductions of bicyclo[2.2.1]heptan-2-one and its derivatives with NaBH₄, AlH₃, and LiAlH₄ probably because of smaller steric hindrance to endo-face hydride attack when C(5) and C(6) of the bicyclo-[2.2.1]heptan-2-one are part of an exo oxirane ring.     

α,β-Unsaturated α′-Halomethylsulfones: Prepackaged Ramberg–Bäcklund Reagents for Tandem Synthetic Processes

Abstract

The synthesis and reactions of several α,β-unsaturated chloromethyl sulfones are presented, for example [(chloromethyl) sulfonyl]-1,3-propadiene, [(chloromethyl) sulfonyl]ethene, [(dichloromethyl)sulfonyl]ethene and (E,Z)-1,2-bis[(chloromethyl)sulfonyl]ethene. These compounds serve as “prepackaged” Ramberg–Bäcklund reagents, which, following an appropriate first step, such as Diels–Alder addition, react with a base, giving Ramberg–Bäcklund products.     

Acid-Catalyzed Rearrangements of 5,6-exo-Epoxy-7-oxabicyclo[2.2.1]hept-2-yl Derivatives. Migratory Aptitudes of Acyl vs. Alkyl Groups in Wagner-Meerwein Transpositions

In the presence of HSO₃F/Ac₂O in CH₂CL₂, 2-exo- and 2-endo-cyano-5,6-exo-epoxy-7-oxabicyclo[2.2.1]hept-2-yl acetates ( 6a , b ) gave products derived from the epoxide-ring opening and a 1,2-shift of the unsubstituted alkyl group (σ bond C(3)–C(4)). In contrast, under similar conditions, the 5,6-exo-epoxy-7-oxabicyclo[2.2.1]heptan-2-one ( 6c ) gave 5-oxo-2-oxabicyclo[2.2.1]heptane-3,7-diyl diacetates 20 and 21 arising from the 1,2-shift of the acyl group. Acid treatment of 5,6-exo-epoxy-2,2-dimethoxy-7-oxabicyclo[2.2.1]heptane ( 6d ) and of 5,6-exo-epoxy-2,2-bis(benzyloxy)-7-oxabicyclo[2.2.1]heptane ( 6e ) gave minor products arising from epoxide-ring opening and the 1,2-shift of σ bond C(3)–C(4) and major products ( 25 , 29 ) arising from the 1,3-shift of a methoxy and benzyloxy group, respectively. Under similar conditions, 5,6-exo-epoxy-2,2-ethylenedioxy-7-oxabicyclo[2.2.1]heptane ( 6f ) gave 1,1-(ethylenedioxy)-2-(2-furyl)ethyl acetate ( 32 , major) and a minor product 33 , arising from the 1,2-shift of σ bond C(3)–C(4). The following order of migratory aptitudes for 1,2-shifts toward electron-deficient centers has been established: acyl > alkyl > alkyl α-substituted with inductive electron-withdrawing groups. This order is valid for competitive Wagner-Meerwein rearrangements involving equilibria between carbocation intermediates with similar exothermicities.     

The 7,8-epoxy-2,3,5,6-tetrakis(methylene) bicyclo[2.2.2]octane; synthesis and diels-alder reactivity

The preparation of 7,8-epoxy-2,3,5,6-tetrakis(methylene)bicyclo[2,2,2] octane (5) is described. Evidence for transannular interaction between the homoconjugated s-cis-butadiene functions in 5 is found in the UV absorption spectrum. The Diels-Alder addition of 5 to tetracyanoethylene (TCE) is syn-regioselective and leads to the monoaducts 16:17 (85:15). The dienes 16,17 are less reactive than 5 toward TCE. anti-regioselectivity (leading to exo-2, endo-3-bis(chloromethyl)-5,6-bis(methylene)-syn-7,8-epoxybicyclo[2.2.2]octaves (25) is observed in the double elimination of HCl from the syn-7,8-epoxy-exo-2,endo-3,exo-5,endo-6-tetrakis(chloromethyl)bicyclo[2.2.2]octane (11), precursor of 5. The structures of the regioisomers 16,17 were confirmed spectroscopically and chemically. Elimination of HCl from the chloromethyl groups in 26 (TCE adduct of 25) and HCN from the TCE adducts 16, 17 and 26 can be induced by CsF in DMF.     

Chemo- and Stereoselective Coordination of 5,6-Dimethylidene-7-oxabicyclo[2.2.1]hept-2-ene by d8- and d6-Metal Carbonyls. Diels-Alder reactivity of Dienes Perturbed by Remote Olefin Complexation

The endocyclic double bond C(2), C(3) in 5,6-dimethylidene-7-oxabicyclo[2.2.1]-hept-2-ene ( 1 ) can he coordinated selectively on its exo-face before complexation of the exocyclic s-cis-butadiene moiety. Irradiation of Ru₃(CO)₁₂ or Os₃(CO)₁₂ in the presence of 1 gave tetracarbonyl [(1R,2R, 3S,4S)-2,3-η-(5,6-dimethylidene-7-oxabicyclo[2.2.1]-hept-2-ene)]ruthenium ( 6 ) or -osmium ( 8 ). Similarly, irradiation of Cr(CO)₆ or W(CO)₆ in the presence of 1 gave pentacarbonyl[(1R, 2R, 3S,4S)-2,3-η-(5,6-dimethylidene-7-oxabicyclo[2.2.1]hept-2-ene)]chromium (10) or -tungsten (11) . Irradiation of complexes 6 and 11 in the presence of 1 led to further CO substitution giving bed-tricarbonyl-ae-bis[(1R,2R,3S,4S)-2,3-η-(5,6-dimethylidene-7-oxabicyclo[2.2.1]hept-2-ene)]ruthenium ( 7 ) and trans-tetracarbonyl[(1R,2R,3S,4S)-2,3-η-(5,6-dimethylidene-7-oxabicyclo-[2.2.1]hept-2-ene)]tungsten (12) , respectively. The diosmacyclobutane derivative cis-m?-[(1R,3R,3S,4S)-(5,6-dimethylidene-7-oxabicyclo[2.2.1]hepta-2,3-diyl)]bis(tetracarbonyl-osmium) (Os-Os) (9) wa also obtained. The Diels-Alder reactivity of the exocyclic s-cis-butadiene moiety in complexs 7 and 8 was found to be significantly higher than that of the free triene 1 .     

Synthesis of Polypropionate Fragments Containing Tertiary-Alcohol Moieties. Cross-aldolisations with lithium enolates of 7-oxabicyclo[2.2.1]heptan-2-one derivatives

The Diels-Alder adduct of 2,4-dimethylfuran to 1-cyanovinyl (1′R)-camphanate ((+)-(1R,2S,4R)-2-exo-cyano-1,5-dimethyl-7-oxabicyclo[2.2.1]hept-5-en-2-endo-yl (1′R)-camphanate ((+)- 1 )) was converted into (+)-2,7-dideoxy-2,4-di-C-methyl-L -glycero- ((+)- 6 ) and -D -glycero-L -altro-heptono-1,4-lactone ((+)- 7 ), into (?)-(3R,4R,5R,6S)-3,4:5,7-bis(isopropylidenedioxy)-4,6-dimethylheptan-2-one ((?)- 22 ), and into (+)-(2R,3R,4R,5S,6S)-3,4:5,6-bis(isopropylidenedioxy)-2,4-dimethylheptanal ((+)- 34 ). Condensation of ((+)- 34 with the lithium enolate of (?)-(1R,4R,5S,6R)-6-exo-[(tert-butyl)dimethylsilyloxy]-1,5-endo-dimethyl-7-oxabicyclo[2.2.1] heptan-2-one ((?)- 38 ; derived from (+)- 1 ) gave a 3:2 mixture of aldols (+)- 39 and (+)- 40 (mismatched pairs of a α-methyl-substituted aldehyde and (E)-enolate) whereas the reaction of (±)- 34 with (±)- 38 gave a 10:1 mixture of aldols (±)- 41 and (±)- 39 . A single aldol, (?)- 44 , was obtained to condensing (+)- 34 with the lithium enolate of (+)-(1S,4S,5S,6S)-5-exo-(benzyloxy)-1,5-endo-dimethyl-7-oxabicyclo[2.2.1]heptan-2-one ((+)- 43 ; derived from (?)-(1S,2R,4S)-2-exo-cyano-1,5-dimethyl-7-oxabicyclo[2.2.1]hept-5-en-2-endo-yl (1′S)-camphanate ((?)- 3 )). All these cross-aldolisations are highly exo-face selective for the bicyclic ketones. The best stereochemical matching is obtained when the lithium enolates and α-methyl-substituted aldehydes can realize a ‘chelated transition state’ that obeys the Cram and Felkin-Anh models (steric effects). Polypropionate fragments containing eleven contiguous stereogenic centres and tertiary-alcohol moieties are thus prepared with high stereoselectivity in a convergent fashion. The chiral auxiliaries ((1R)- and (1S)-camphanic acid) are recovered at the beginning of the syntheses.     

Circular Dichroism of Planar,Exocyclic S-cis-Butadienes Remotely Perturbed

Optically pure 5,6-dimethylidenebicyclo[2.2.1]hept-2-yl derivatives have been prepared. The sign of the Cotton effects associated with lowest-energy transition of 2–(dicyanomethylidene)-((?)-(1S,4S)- 15 ), (E)-2-(methoxyimino)-((+)-(1S,4S)- 16 ), (Z)-2-(methoxyimino)-5,6-dimethylidenebicyclo[2.2.1]heptane ((?)(1S,4S)- 17 ), and 2,3,5-trimethylidenebicyclo[2.2.1]heptane ((?)-(1R,4S)- 18 ) is opposite to the chirality constituted by the coupling of the electric transition moments of the two homoconjugated π-chromophores (Kuhn-Kirkwood dipole-coupling mechanism). When the substituents at C(2) are not π-functions, no general rule can be retained for the chiroptical properties of the 5,6-dimethylidenebicyclo[2.2.1]hept-2-yl systems as shown for dimethyl acetal (?)-(1S,4S)- 19 , ethylene acetal (+)-(1R,4R)- 20 , exo and endo methyl ethers (+)-(1R,2S,4R)- 21 and (+)-(1R,2R,4R)- 22 , and for spirol[5,6-dimethylidenebicyclo[2.2.1]heptane-2.2'-oxiranes](?)-(1S,2S,4S)- 23 and (?)-(1S,2S,4S)- 24 .     

Sterical Hindrances as a Driving Force of Skeleton Rearrangements of Fenchone and Its Oxime in Ritter Reaction

Fenchone (1,3,3-trimethylbicyclo[2.2.1]heptan-2-one) in reaction with acetonitrile in the presence of sulfuric acid (Ritter reaction) due to steric hindrances preventing geminal addition of two nucleophile molecules gives rise to a mixture of 1,2-exo-diacetamido-6-endo,7,7-trimethylbicyclo[2.2.1]heptane, 2-endo6-exo-diacetamido-3,3,6-trimethylbicyclo[2.2.1]heptane, and 2-exo,6-exo-diacetamido-1,3,3-tri- methylbicyclo[2.2.1]heptane in the ratio of 6:4:1. Fenchone oxime under condition of this reaction affords a mixture of stereoisomeric cis- and trans-acetamido-1-methyl-3-(-cyanoisopropyl)cyclopentanes in 2:3 ratio.     

Face Selectivity in the Diels-Alder Additions and Chelotropic Addition of Sulfur Dioxide to 2-(D)Methylidene-3-methylidenebicyclo[2.2.1]heptane

The stereoselectivity of the cycloadditions of 2-(D)methylidene-3-methylidenebicyclo[2.2.1]heptane ( 4 ) to various dienophiles has been determined. The exo- vs. endo-face selectivity depends on the type of dienophiles, and for olefinic ones, on the mode of attack (Alder- vs. anti-Alder endo rule). It is > 9:1 with N-phenyltriazolinedione (NPTAD) and ethylenetetracarbonitrile (TCNE), < 1:9 with dimethyl acetylenedicarboxylate (DMAD), 30 ± 5:70 ± 5 with DMAD in the presence of AlCl₃, 15 ± 5:85 ± 5 with dehydrobenzene and 40 ± 5:60 ± 5 with ¹O₂ generated photochemically (Table 1). With para-benzoquinone and maleic anhydride, the exo- vs. endo- face selectivity is < 1:9 and 20 ± 5:80 ± 5, respectively, for their anti-Alder mode of attack; it is 50 ± 5:50 ± 5 and 55 ± 5:45 ± 5, respectively, for their Alder mode of reaction. Under conditions of kinetic control, the chelotropic addition of SO₂ to 4 is endo-face selective.     

Extensive hydrogen and halogen bonding,and absence of intramolecular hydrogen bonding between alcohol and nitro groups in a series of endo‐nitronorbornanol compounds

The influence of the substituent at the C2 position on the hydrogen‐bonding patterns is compared for a series of five related compounds, namely (±)‐3‐exo,6‐exo‐dibromo‐5‐endo‐hydroxy‐3‐endo‐nitrobicyclo[2.2.1]heptane‐2‐exo‐carbonitrile, C₈H₈Br₂N₂O₃, (II), (±)‐3‐exo,6‐exo‐dibromo‐6‐endo‐nitro‐5‐exo‐phenylbicyclo[2.2.1]heptan‐2‐endo‐ol, C₁₃H₁₃Br₂NO₃, (III), (±)‐methyl 3‐exo,6‐exo‐dibromo‐5‐endo‐hydroxy‐3‐endo‐nitrobicyclo[2.2.1]heptane‐2‐exo‐carboxylate, C₉H₁₁Br₂NO₅, (IV), (±)‐methyl 3‐exo,6‐exo‐dibromo‐7‐diphenylmethylidene‐5‐endo‐hydroxy‐3‐endo‐nitrobicyclo[2.2.1]heptane‐2‐exo‐carboxylate, C₂₂H₁₉Br₂NO₅, (V), and (±)‐methyl 3‐exo,6‐exo‐dibromo‐5‐endo‐hydroxy‐3‐endo‐nitro‐7‐oxabicyclo[2.2.1]heptane‐2‐exo‐carboxylate, C₈H₉Br₂NO₆, (VI). The hydrogen‐bonding motif in all five compounds is a chain, formed by O—H...O hydrogen bonds in (III), (IV), (V) and (VI), and by O—H...N hydrogen bonds in (II). All compounds except (III) contain a number of Br...Br and Br...O halogen bonds that connect the chains to each other to form two‐dimensional sheets or three‐dimensional networks. None of the compounds features intramolecular hydrogen bonding between the alcohol and nitro functional groups, as was found in the related compound (±)‐methyl 3‐exo,6‐exo‐dichloro‐5‐endo‐hydroxy‐3‐endo‐nitrobicyclo[2.2.1]heptane‐2‐exo‐carboxylate, (I) [Boeyens, Denner & Michael (1984b). J. Chem. Soc. Perkin Trans. 2, pp. 767–770]. The crystal structure of (V) exhibits whole‐molecule disorder.     

Stereoselective additions to the exocyclic CC bond of some α-alkylidene-(+)-camphor derivatives

Stereoselective additions to the exocyclic CC double bond of some (1R,3E,4S)-3-alkylidene-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ones and (1R,4E,5S)-4-alkylidene-1,8,8-trimethyl-2-oxabicyclo[3.2.1]octan-3-ones were studied. All additions took place predominantly from the less hindered endo-face of the methylidene compounds to give the corresponding exo-adducts as the major isomers. Thus, catalytic hydrogenations afforded the α-alkylated (1R,3R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ones and (1R,4R,5R)-1,8,8-trimethyl-2-oxabicyclo[3.2.1]octan-3-ones in 28–100% de. Similarly, 1,3-dipolar cycloadditions of 2,4,6-trisubstituted benzonitrile oxides gave the corresponding spiro cycloadducts in 66–100% de. The structures were determined by 2D NMR techniques, NOESY spectroscopy and X–ray diffraction.     

Chiral exo-Alkylidenecyclopentanes from (1S,4R)-7,7-Dimethyl-1-vinylbicyclo[2.2.1]heptan-2-one

(1S,4R)-7,7-Dimethyl-1-vinylbicyclo[2.2.1]heptan-2-one oxime in the system (CF₃CO)₂O-CF₃COOH and (1S,4R)-1-(1,2-dibromoethyl)-7,7-dimethylbicyclo[2.2.1]heptan-2-one in the system MeONa-MeOH undergo fragmentation to give exo-alkylidenecyclopentane derivatives, (4R)-4-cyanomethyl-5,5-dimethyl-1-[(1E)-trifluoroacetoxyethylidene]cyclopentane and isomeric (4R)-4-carboxymethyl-1-[(1ZE)-2-methoxyethylidene]-5,5-dimethylcyclopentanes, respectively. The trifluoroacetate derivative undergoes unusual rearrangement, yielding an equilibrium mixture of two isomers with endo- and exocyclic double bond.     

Prepackaged Ramberg-Bäcklund reagents: useful tools for organic synthesis

The synthesis and reactions of several α,β-unsaturated chloromethyl sulfones is presented, for example [(chloromethyl)sulfonyl]-1,3-propadiene (4), [(chloromethyl)sulfonyl]ethene (5), [(dichloromethyl)sulfonyl]ethene (6) and (E,Z)-1,2-bis[(chloromethyl)sulfonyl]ethene (7). These compounds serve as ‘prepackaged’ Ramberg-Bäcklund reagents, which following an appropriate first step, such as Diels-Alder addition, react with base giving Ramberg-Bäcklund products.     

Camphor and Isocamphanone in the Synthesis of Disubstituted Acetylene Alcohols,Ethers, and Esters

By treating 1-octyne and phenylacetylene with butyllithium the corresponding lithium acetylides were obtained that with camphor and isocamphanone provided along streospecific process 2-exo-(1-octynyl or 2-phenyl-1-ethynyl)-2-endo-lithiumoxy-5,5,6-trimethylbicyclo[2.2.1]heptane and 2-endo-(1-octynyl or 2-phenyl-1-ethynyl)-2-exo-lithiumoxy-1,7,7-trimethylbicyclo[2.2.1]heptane. The hydrolysis of these lithium alcoholates occurred selectively and resulted in individual tertiary terpene alcohols containing exo-acetylene substituent in the case of camphor, endo-acetylene fragment in the case of isocamphanone. The alcohols reacted with methyl, ethyl, or butyl iodides in the presence of hexamethylphosphoramide to afford ethers, and with benzoyl chloride to furnish disubstituted esters of benzoic acid.     

Synthesis,structure, and transformations of <Emphasis Type="Italic">N</Emphasis>-(alkyl-, benzyl-, arylsulfonyl)-<Emphasis Type="Italic">N</Emphasis>-(oxiran-2-ylmethyl)bicyclo[2.2.1]hept-5-en-<Emphasis Type="Italic">exo</Emphasis>-2-ylmethanamines

Reactions of N-(alkyl-, benzyl-, arylsulfonyl)bicyclo[2.2.1]hept-5-en-exo-2-ylmethanamines with 2-(chloromethyl)oxirane in the presence of tetramethylammonium iodide gave a number of cage-like N-(oxiran-2-ylmethyl)sulfonamides, as well as N-(exo-5,6-epoxybicyclo[2.2.1]heptan-exo-2-ylmethyl)-4-nitro-N-(oxiran-2-ylmethyl)benzenesulfonamide. The latter was also synthesized by oxidation of oxiran-2-ylmethyl norbornene derivative with peroxy acids. Opening of the epoxide ring in N-(oxiran-2-ylmethyl) sulfonamides in reaction with benzylamine followed the Krasuskii rule, and the aminolysis of N-(exo-5,6-epoxybicyclo[2.2.1]-heptan-exo-2-ylmethyl)-4-nitro-N-(oxiran-2-ylmethyl)benzenesulfonamide chemoselectively occurred at the side-chain epoxy group.