Synthesis of 2-amino-1,3-dienes by chromium-catalyzed addition of silylated propargyl bromides to imines

(Silyl)methylallenic amines were synthesized by the chromium-catalyzed addition of (4-bromobutynyl)trimethylsilane to tosyl imines. Regioisomeric mixtures of the desired allene and the corresponding alkyne were obtained. Allenic imines were then treated with TBAF to afford 2-aminomethyl-1,3-dienes in good yields (62-92%). In the presence of a Lewis acid, silylallenic imines were added to benzaldehyde dimethylacetal to give highly functionalized dienes with excellent yields and good to excellent diastereomeric ratios.     

Synthesis and acylation of tertiary enamines: 1,2,3,4-tetrahydroisoquinoline derivatives

N-methyl-3,3-R¹R²-1-(R³-methylene)-1,2,3,4-tetrahydroisoquinolines were obtained; they react with acylating agents forming enaminocarbonyl derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 939–942, July, 1988.     

Aromatic fluoro derivatives XLIX. Synthesis of carbocyclic compounds by intramolecular nucleophilic substitution reactions

Interaction of a compound of the type

with sodium hydride results in the formation of the Na salt of the carbanion

(where Ar_F represents a polyfluorinated group), which can enter into an intramolecular nucleophilic substitution reaction with the formation of the corresponding polyfluorinated carbocyclic compound. This reaction may serve as a general method for producing such compounds.     

Direct synthesis of NNN-donor enantiopure scorpionate ligands by an efficient diastereoselective nucleophilic addition to imines

New enantiopure imines (1-9) with a chiral substrate to control the stereochemistry of a newly created stereogenic center have been synthesized by reaction of the commercially available (1R)-(-)-myrtenal and different primary amines. The diastereomerically enriched lithium-scorpionate compounds [Li(κ(3)-mobpza)(THF)] (10) (mobpza = N-p-methylphenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethylamide), [Li(κ(3)-mobpza)(THF)] (11) (mobpza = N-p-methoxyphenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethylamide), [Li(κ(3)-fbpza)(THF)] (12) (fbpza = N-p-fluorophenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethylamide), and [Li(κ(3)-clbpza)(THF)] (13) (clbpza = N-p-chlorophenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethylamide) were obtained by a diastereoselective 1,2-addition of an organolithium reagent to imines in good yield and with good diastereomeric excess (ca. 80%). The complexes [LiCl(κ(2)-R,R-fbpzaH)(THF)] (14) and [LiCl(κ(2)-R,R-clbpzaH)(THF)] (15) were obtained in enantiomerically pure form by the treatment of THF solutions of 12 or 13 with NH(4)Cl. The enantiomerically pure amines (R,R-mbpzaH) (16), (R,R-mobpzaH) (17), (R,R-fbpzaH) (18), and (R,R-clbpzaH) (19) were obtained by hydrolysis of the lithium-scorpionate compounds 10-13 with H(2)O. The lithium compound 12 was reacted with [TiCl(4)(THF)(2)] or [ZrCl(4)] to give the enantiopure complexes [MCl(3)(κ(3)-R,R-fbpza)] [M = Ti (20), Zr (21)]. The amine compound 18 reacted with [MX(4)] (M = Ti, X = O(i)Pr, OEt; M = Zr; X = NMe(2)) to give the complexes [MX(3)(κ(3)-R,R-fbpza)] (22-24). The reaction of Me(3)SiCl with [Zr(NMe(2))(3)(κ(3)-R,R-fbpza)] (24) in different molar ratios led to the halide-amide-containing complexes [ZrCl(NMe(2))(2)(κ(3)-R,R-fbpza)] (25) and [ZrCl(2)(NMe(2))(κ(3)-R,R-fbpza)] (26) and the halide complex 21. The isolation of only one of the three possible diastereoisomers of complexes 25 and 26 revealed that chiral induction from the ligand to the zirconium center took place. The structures of these compounds were elucidated by (1)H and (13)C{(1)H} NMR spectroscopy, and the X-ray crystal structures of 5, 12, 14, 15, and 24 were also established.     

Activation of the Si-B linkage: copper-catalyzed addition of nucleophilic silicon to imines

Activation of the Si-B bond through copper-catalyzed transmetalation quickly developed into a practical method to generate Cu-Si reagents. These silicon nucleophiles cleanly add to aldehyde-derived imine electrophiles to form α-silylated amines in protic media, and no carbon-to-nitrogen Brook-type rearrangement of the intermediate anion is observed. Aside from electron-withdrawing groups at the imine nitrogen atom, for example, SO(2)Tol and P(O)Ph(2), previously delicate nitrogen substituents such as phenyl or benzhydryl are tolerated. The same protocol also allows the unprecedented addition to representative ketone-derived imines.     

Synthesis of 1,2,3,4-tetrahydro-4-pyridinones by heterocyclization of β-amino-β-arylacryloyloxiranes

The heterocyclization of -alkyl(phenyl)aminocinnamoyloxiranes and their -bromo derivatives under base-catalysis conditions is a convenient method for the synthesis of 3-hydroxytetrahydro-4-pyridinones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 347–350, March, 1989.     

Novel 2-pyridone synthesis via nucleophilic addition of malonic esters to alkynyl imines

[reaction: see text] A novel 2-pyridone synthesis via nucleophilic addition of malonic esters to alkynyl imines has been developed. The reaction of dialkylalkyl sodiomalonates with alkynyl imines provided 2-pyridones in good to excellent yields.     

Synthesis of 1-oxa-2-silacyclopentane derivatives via intramolecular nucleophilic attack at silicon

Metalation of (HSiMe₂)₃CH with lithium diisopropylamide (LDA) in THF gives (HSiMe₂)₃CLi, which reacts with ethylene oxide, propylene oxide, 1,2-epoxy butane, 1,2-epoxy pentane, 1,2-epoxy hexane, and epichlorohydrin to give the corresponding 1-oxa-2-silacyclopentane derivatives. Then, glycidylmethacrylate (GM) random copolymers with styrene (St) (in a 1:1 and 1:3 mol ratio) were synthesized by solution free radical polymerization at 70(±1) °C using α,α′-azobis(isobutyronitrile) (AIBN) as an initiator. Both types of copolymers were treated with (HSiMe₂)₃CLi to give new modified copolymers. The reaction of (HSiMe₂)₃CLi with epoxides on the side chains of the copolymers does not lead to intramolecular nucleophilic attack contrary to simple epoxides. All the products have been characterized by spectroscopic techniques.     

Synthesis of polynitroalcohols by nucleophilic addition of butadiene-styrene nitrooligomer to acetaldehyde

Two types of secondary polynitroalcohols (PNA) were prepared by A_N-reaction of butadiene-styrene nitrooligomer (BSNO) and acetaldehyde. The corresponding yields were 58-64% and 25-33%. The reaction was conducted in water-ethanol solution in the presence of alkaline base as catalyst at temperatures from 40 to 60 °C, for 3.5-4 h. Introduction of hydroxyethyl groups by A_N-reaction of BSNO to acetaldehyde increased the polarity and thermal stability of PNA as compared to BSNO. By using IR spectroscopy and liquid absorption chromatography on silica gel, PNA were found to be polyfunctional compounds, that contained structurally and functionally heterogeneous fractions. The quantitative functional composition of the first PNA type as well as their main fractions were determined by evaluating the relative content of nitro-, carbonyl and hydroxyl groups in the products. PNA are considered to be starting materials for the preparation of polynitrourethanes and salts of N-containing sulphonic acids.     

Synthesis of 9-amino-, 9-aminomethyl-1,2,3,4-tetrahydro- and 1,2,3,4,5,6,7,8-octahydroacridine derivatives

This paper describes the synthesis of 9-amino-2- and 4-hydroxy- and 2,4-dihydroxy-1,2,3,4-tetrahydro-acridines 2 and of 9-aminomethyl-1,2,3,4-tetrahydro- and 1,2,3,4,5,6,7,8-octahydroacridines 3 starting from the corresponding 9-carboxamido derivatives. A new synthetical pathway to 9-amino-2-hydroxyacri-dine 9 is also reported.     

Catalytic enantioselective addition of arylboronic acids to N-boc imines generated in situ

The rhodium-catalyzed addition of arylboronic acids to N-Boc imines generated in situ from stable and easily prepared alpha-carbamoyl sulfones has been developed. High enantioselectivities are observed for additions of arylboronic acids with a variety of steric and electronic properties.     

Efficient palladium-catalyzed nucleophilic addition of triorganoindium reagents to carbocyclic derivatives

Palladium (0)-catalyzed allylic substitution reactions employing triorganoindium reagents have been investigated. In situ generated vinyl- and arylindiums react with substituted and unsubstituted cyclohex-2-enyl esters in the presence of 1-3 mol % Pd(2)(dba)(3) to produce vinyl- or arylcyclohexenes in moderate to excellent yields. The stereoselectivity of this process was also examined, and evidence is presented that the reaction proceeds with inversion of stereochemical configuration.