Acyl iodides in organic synthesis: VIII. Reactions with amino acids

Reactions of acyl iodides RCOI (R=Me, Ph) with glycine, β-alanine, and γ-aminobutyric acid were investigated. The reaction proceeded easily at room temperature without solvent involving both functional groups H₂N and COOH. The prevalence of one of the reaction directions depends on the acidity of the amino acid. The more acidic glycine (pК_a 2.4) reacts with RCOI affording mainly N-acylated product, whereas β-alanine (pК _a 3.60) and especially γ-aminobutyric acid (pК_a 4.06) are predominantly involved into exchange iodination furnishing the corresponding aminoacyl iodides.     

Acyl iodides in organic synthesis: XII. Reactions with organosilicon amines

Reactions were investigated between acyl iodides RCOI (R = Me, Ph) and organosilicon amines of two classes: trimethyl(diethylamino)silane, dimethyl-bis(diethylamino)silane, and hexamethyldisilazane on the one hand, and 3-aminopropyl(triorganyl)silanes H₂N(CH₂)₃SiX₃ (X = Et, EtO) on the other hand. The reaction of RCOI with trimethyl(diethylamino)silane Me₃SiNEt₂ occurred with a cleavage of the Si-N bond and the formation of N,N-diethylacet- or -benzamides and trimethyliodosilane separated in a mixture with hexamethyldisiloxane. At the reaction of acyl iodides RCOI (R = Me, Ph) with dimethyl-bis(diethylamino)silane in the ratio 2:1 in benzene solution both Si-N were ruptured leading to the diethylamide of the corresponding acid and dimethyldiiodosilane. The main product of the reaction of acetyl iodide with hexamethyldisilazane at the molar ratio 2:1 was diacetylimide (MeCO)₂NH. This reaction can be recommended as a simple and convenient preparation procedure for diacylimides. The exothermal reaction of the acetyl iodide with 3-aminopropyl(triethyl)- and -(triethoxy)silanes at the molar ratio of the reagents 1:1 without solvent resulted in quaternary ammonium salts, hydroiodides of the corresponding acetylamides I^?MeCON⁺H₂(CH₂)₃SiX₃ (X = Et, OEt).     

Acyl Iodides in Organic Synthesis: II. Reactions with Acyclic and Cyclic Ethers

Reaction of acyl iodides RCOI (R = Me, Ph) was studied with acyclic and cyclic ethers (Et₂O, MeCHCH₂(O), ClCH₂CHCH₂(O), THF, O(CH₂CH₂)₂O, EtOCH₂CH₂OH, EtOCH = CH₂, PhOEt]. The reaction occurred with the rupture of one or two CO bonds furnishing the corresponding iodides and esters.     

Acyl Iodides in Organic Synthesis. Reaction of Acyl Iodides with <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-Dimethyl Carboxylic Acid Amides

Acyl iodides RCOI (R = Me, Ph) reacted with N,N-dimethylformamide and N,N-dimethylacetamide Me₂NC(=O)R’ (R’ = H, Me) along two concurrent pathways involving transacylation and cleavage of the Me-N bond. The first pathway leads to the formation of acyl group exchange products, and the second, to the corresponding imides R’CON(Me)COR.     

Expected and unexpected photochemical reactions of acyl iodides

Photolysis of acyl iodides RCOI (R = Me, Me₂CH, Ph) under UV irradiation in toluene environment for 20–55 h proved to be a simple and efficient method of preparation of symmetrical α-diketones RCOCOR. In contrast, the photolysis under the same conditions of acyl iodides RCOI [R = Me(CH₂)₃, Me₃C] did not lead to the formation of the corresponding diacyls, and the reaction products were unexpected 1,1-bis(4-methylphenyl)pentane and a mixture of isomeric 3- and 4-methyl(tert-butyl)benzenes respectively. The most probable mechanism of their formation is the primary photochemical acylation of toluene in the aromatic ring followed by the photochemical reduction of the arising butyl 4-methylphenyl ketone in the case of the valeroyl iodide or the photochemical Norrish type I cleavage of isomeric 3- and 4-methylphenyl (tert-butyl) ketones in event of the pivaloyl iodide. In the photolysis of acetyl iodide (R = Me) in benzene or toluene alongside the diacetyl formation polyarylation process was observed of acylated and iodinated into the aromatic ring solvents with the formation of polymeric products with semiconductor and paramagnetic properties.     

Coordination complexes of acetylenic phosphines and diphosphines : V. Acetylene bridged derivatives of dicobalt octacarbonyl

Reactions of the phosphinoacetylenes RR′PCCR″ (R  R′  Ph, R″  H, CF₃, Ph, Me, t-Bu; R  R′  C₆F₅, R″  Ph, Me; R  Ph, R′  Me, R″  Me) with Co₂(CO)₈ have been studied. Complexes of four types have been characterised: (A)(RR′PC₂R″)CO₂(CO)₆ (R  R′  C₆F₅, R″  Ph, Me; R  R′  Ph, R″  t-Bu), (B) (RR′PC₂R″)₂Co₄(CO)₁₀ (R  R′  Ph, R″  H, CF₃, Ph, Me; R  R′  C₆F₅, R″  Me; R  Ph, R′  Me, R″  Me), (C) (RR′PC₂R″)₂Co₂(CO)₆ (R  R′  Ph, R″  t-Bu), (D) (RR′P(O)C₂R″)Co₂(CO)₆ (R  R′  Ph, R″  t-Bu; R  R′  C₆F₅, R  Ph). The complexes were characterised by microanalysis, IR, NMR and where possible mass spectra. Substitution reactions of the complexes with tertiary phosphites are described. In complexes of type (A) only the alkyne function is utilised whereas the tetranuclear compounds (B) have structures in which both alkyne and phosphorus moieties are coordinated. Compounds of type (C) are simple disubstituted phosphine complexes of Co₂(CO)₈ and those of type (D) are μ-alkyne derivatives of acetylenic phosphine oxides. The mechanism of formation of complexes of type (B) is discussed in the light of IR data.     

Synthesis of N-[chloro(diorganyl)silyl]anilines

A series of N-[chloro(diorganyl)silyl]anilines RR′Si(NR″Ph)Cl (R, R′ = Me, Ph, CH₂=CH, ClCH₂, Cl(CH₂)₃; R″ = H, Me) was prepared via the reaction of diorganyldichlorosilanes with aniline or N-ethylaniline in the presence of triethylamine.     

Acyl Iodides in Organic Synthesis: I. Reactions with Alcohols

Reaction of acyl iodides RC(O)I (R = Me, Ph) with alcohols R'OH (R' = Me, Et, i-Pr, t-Bu, CH₂ = CHCH₂, HCCCH₂) provides in the corresponding organyl iodides R'I. Unlike that 2-chloroethanol and phenol (R' = CH₂CH₂Cl, Ph) react with RC(O)I in the same way as with acyl chlorides yielding esters RCO₂R'. This reaction path occurs partially also with methanol and ethanol.     

The preparation and characterisation of a series of cationic bimetallic linear triphos-bridged complexes of the type [Mo (CO) (L,L′ or L″–P) (η2-RC2R′)Cp] [BF4] {L,L′ or L″= [WI2 (CO){PhP(CH2CH2PPh2)2–P,P′} (η2-RC2R′)] (L,R=R′=Me; L′,R=R′=Ph; L″,R=Me,R′=Ph}

Equimolar quantities of [Mo (CO) (η²-RC₂R′)₂Cp] [BF₄] (R=R′=Me Ph R=Me R′=Ph) and L L′ or L″ {L L′ or L″= [WI₂ (CO){PhP(CH₂CH₂PPh₂)₂-PP′} (η²-RC₂R′)]} (L R=R′=Me L′ R=R′=Ph L″ R=Me R′=Ph) react in CH₂Cl₂ at room temperature to give the new bimetallic complexes[Mo (CO) (L L′ or L″–P) (η²-RC₂R′)Cp] [BF₄] (1–9) via displacement of the alkyne ligand on the molybdenum centre The complexes have been characterised by elemental analysis IR and ¹ H NMR spectroscopy and in selected cases by ³¹ P NMR spectroscopy.     

Acyl iodides in organic synthesis: IX. Cleavage of the Si-O-C and Si-O-Si moieties

Reactions of acyl iodides RCOI (R = Me, Ph) with organosilicon compounds involve cleavage of the Si-O-C and Si-O-Si fragments. Acetyl iodide reacts with alkyl(alkoxy)silanes with evolution of heat, and cleavage of the Si-O bond results in the formation of oligo-or polysiloxanes, alkyl iodides, and alkyl acetates. 1,3-Diacetoxytetramethyldisiloxane is formed in the reaction of acetyl iodide with dimethoxy(dimethyl)silane. Acyl iodides readily react with 1-ethoxysilatrane to give 1-acyloxysilatranes as a result of cleavage of the C-O bond. The reaction of acetyl iodide with hexaethyldisiloxane yields triethylsilyl acetate and triethyliodosilane, while in the reaction with octamethyltrisiloxane iodo(trimethyl)silane and dimethyl(trimethylsiloxy)silyl acetate are obtained.     

Acyl iodides in organic synthesis. Reactions with morpholine,piperidine, and <Emphasis Type="Italic">N</Emphasis>-hydrocarbylpiperidines

Acyl iodides RCOI (R = Me, Ph) reacted with morpholine and piperidine to give the corresponding N-acyl derivatives and morpholine or piperidine hydroiodides. Reactions of acyl iodides with N-methyl- and N-ethylpiperidines involved cleavage of the exocyclic R-N bond with formation of N-acylpiperidine and alkyl iodide and were accompanied (to insignificant extent) by cleavage of the endocyclic N-C bond, leading to N-alkyl-N-(5-iodopentyl)acylamides. In the reaction of acetyl iodide with N-phenylpiperidine, the main process was cleavage of just endocyclic N-C bond to produce N-(5-iodopentyl)-N-phenylacetamide and its dehydroiodination product, N-(pent-4-en-1-yl)-N-phenylacetamide. Analogous reaction with benzoyl iodide afforded N-(5-iodopentyl)-N-phenylbenzamide in a poor yield.     

Selektive Darstellung zweifach diorganophosphido-verbrückter Metallatetrahedrane [Re2(MPR3)2(μ-PR2)2(CO)6] mit Re2M2-Metallgerüst (M = Au,Ag)

Selective Preparation of Twofold Diorganophosphido-bridged Metallatetrahedranes [Re₂(MPR₃)₂(μ-PR₂)₂(CO)₆] with Re₂M₂ Metal Core (M = Au, Ag) The reaction of the in situ prepared salt Li[Re₂(AuPR)(μ-PR₂)(CO)₇Cl] (R = R′ = Cy ( 1 a ), R = Cy, R′ = Ph ( 1 b ), R = Ph, R′ = Cy ( 1 c ), R = Ph, R′ = Et ( 1 d ), R = Ph, R′ = Ph ( 1 e )) with one equivalent HPR in methanolic solution at room temperature yields the neutral cluster complexes [Re₂(AuPR)(μ-PR₂)(CO)₇(ax-HPR) (R = R′ = R″ = Cy ( 2 a ), Ph ( 2 b ), R = R′ = Cy, R″ = Et ( 2 c ), R = Cy, R′ = R″ = Ph ( 2 d ), R = Cy, R′ = Ph, R″ = Et ( 2 e ), R = R″ = Ph, R′ = Et ( 2 f ), R = Ph, R′ = Cy, R″ = Et (2 g)). Photochemically induced these complexes react in the presence of the organic base DBU in THF solution to give the doubly phosphido bridged anions Li[Re₂(AuPR)(μ-PR₂)(μ-PR)(CO)₆], which were characterized as salts PPh₄[Re₂(AuPR)(μ-PR₂)(μ-PR)(CO)₆] (R = R′ = R″ = Ph ( 3 a ), R = R′ = Ph, R″ = Cy ( 3 b ), R = Ph, R′ = Cy, R″ = Et ( 3 c ), R = R″ = Ph, R′ = Et ( 3 d )). These precursor complexes 3 then react with one equivalent of ClMPR (M = Au, Ag) to doubly phosphido bridged metallatetrahedranes [Re₂(MPR₃)₂(μ-PR₂)(μ-PR)(CO)₆] (M = Au, R = R′ = R″ = Ph ( 4 a ), M = Au, R′ = Et, R = R″ = Ph ( 4 b ), M = Au, R = R′ = Ph, R″ = Cy ( 4 c ), M = Au, R = Cy, R′ = Ph, R″ = Et ( 4 d ), M = Ag, R = R′ = R″ = Ph ( 4 e )). All isolated cluster complexes were characterized and identified by the following analytical methods: NMR- (¹H, ³¹P) and ν(CO) IR-spectroscopy and, additionally, complexes 2 b , 4 a and 4 e by X-ray structure analysis.     

Dynamics and structure of some tricarbonylferrole-iron tricarbonyl derivatives

A series of compounds of the formula Fe₂(CO)_6-x(PR₃)_x(R′C₂R″)₂ (x = 0, R′ and R″ = Ph, R′ and R″ = H, R′ = Ph and R″ = H; x = 1, K = Ph or n-Bu, and R′ and R″ = Ph) were studied by ¹³C NMR to observe their solution properties. The tricarbonylferrole unit was found to be static from ?125 to +95° C, while the π-Fe(CO)₃ group appeared to be fluxional over the same temperature range. Definite assignments of the carbonyl carbon and ferrole ring carbon resonances have been made. A low temperature single crystal X-ray study of Fe₂(CO)₅PPh₃(PhC₂Ph)₂ demonstrated that the phosphine ligand was attached to the ferrole iron contrary to previous belief based on chemical evidence.     

Reaktionen von Lithiumhydridosilylamiden RR′(H)Si–N(Li)R″ mit Chlortrimethylsilan in Tetrahydrofuran und unpolaren Lösungsmitteln: N‐Silylierung und/oder Cyclodisilazanbildung

Reactions of Lithium Hydridosilylamides RR′(H)Si–N(Li)R″ with Chlorotrimethylsilane in Tetrahydrofuran and Nonpolar Solvents: N‐Silylation and/or Formation of Cyclodisilazanes The lithiumhydridosilylamides RR′(H)Si–N(Li)R″ ( 2 a : R = R′ = CHMe₂, R″ = SiMe₃; 2 b : R = R′ = Ph, R″ = SiMe₃; 2 c : R = R′ = CMe₃, R″ = SiMe₃; 2 d : R = R′ = R″ = CMe₃; 2 e : R = Me, R′ = Si(SiMe₃)₃, R″ = CMe₃; 2 f – 2 h : R = R′ = Me, f : R″ = 2,4,6‐Me₃C₆H₂, g : R″ = SiH(CHMe₂)₂, h : R″ = SiH(CMe₃)₂; 2 i : R = R′ = CMe₃, R″ = SiH(CMe₃)₂) were prepared by reaction of the corresponding hydridosilylamines RR′(H)Si–NHR″ 2 a – 2 i with n‐butyllithium in equimolar ratio in n‐hexane. The unknown amines 1 e – 1 i and amides 2 f – 2 i have been characterized spectroscopically. The wave numbers of the Si–H stretching vibrations and ²⁹Si–¹H coupling constants of the amides are less than of the analogous amines. This indicates a higher hydride character for the hydrogen atom of the Si–H group in the amide in comparison to the amines. The ²⁹Si‐NMR chemical shifts lie in the amides at higher field than in the amines. The amides 2 a – 2 c and 2 e – 2 g react with chlorotrimethylsilane in THF to give the corresponding N‐silylation products RR′(H)Si–N(SiMe₃)R″ ( 3 a – 3 c , 3 e – 3 g ) in good yields. In the reaction of 2 i with chlorotrimethylsilane in molar ratio 1 : 2,33 in THF hydrogen‐chlorine exchange takes place and after hydrolytic work up of the reaction mixture [(Me₃C)₂(Cl)Si]₂NH ( 5 a ) is obtained. The reaction of the amides 2 a – 2 c , 2 f and 2 g with chlorotrimethylsilane in m(p)‐xylene and/or n‐hexane affords mixtures of N‐substitution products RR′(H)Si–N(SiMe₃)R″ ( 3 a – 3 c , 3 f , 3 g ) and cyclodisilazanes [RR′Si–NR″]₂ ( 6 a – 6 c , 6 f , 6 g ) as the main products. In case of the reaction of 2 h the cyclodisilazane 6 h was obtained only. 2 c – 2 e show a very low reactivity toward chlorotrimetyhlsilane in m‐xylene and toluene resp.. In contrast to Me₃SiCl the reactivity of 2 d toward Me₃SiOSO₂CF₃ and Me₂(H)SiCl is significant higher. 2 d react with Me₃SiOSO₂CF₃ and Me₂(H)SiCl in n‐hexane under N‐silylation to give RR′(H)Si–N(SiMe₃)R″ ( 3 d ) and RR′(H)Si–N(SiHMe₂)R″ ( 3 d ′) resp. The crystal structures of [Me₂Si–NSiMe₃]₂ ( I ) ( 6 f , 6 g and 6 h ) have been determined.     

Reactions of Titanium Alkoxides with N-Methylaminoalcohols

N-methylaminoalkoxides of titanium of the type Ti(OR)_4?n(O · CHR′ · CH₂ · NR″R?)_n where R = Et and Pr¹; n = 1–4; and R′ = R″ = H, R? = Me; R′ = H, R″ = R? = Me; R′ = R″ = R? = Me, synthesized by the reactions of titanium alkoxides with aminoalcohols, show interesting variations in their properties like physical state, volatility and molecular complexity. I.r. and p.m.r. spectra of these derivatives have been recorded. A few interchange reactions with methanol and tert-butanol have also been carried out. These aminoalkoxides get cleaved with acetyl chloride and undergo insertion reactions with phenylisocyanate, thus providing the first examples of insertion reactions in such derivatives.     

Insertion Reactions of Carbon Disulfide into Mg‐C and Mg‐N Bonds: Syntheses and Structural Determinations of Mg(S2CY)2(THF)n(Y=NEt2, NiPr2, iPr,Ph) and BrMg(S2CZ)(THF)3(Z=Ph,iPr)

The insertion reaction of CS₂ with Mg(NR₂)₂ (R= Et, ⁱPr), MgR′₂ (R′= Et, Ph) and R″MgBr (R″= ⁱPr, Ph) respectively lead solid products, Mg(S₂CNR₂)₂(THF)_n ( 1 : R= Et, n=2; 2 : R= ⁱPr, n=1), Mg(S₂C′R)₂(THF)₂ ( 3 : ′R= Et, 4 : ′R= Ph), BrMg(S₂C″R) (THF)₃ ( 5 : ″R= ⁱPr, 6 : ″R= Ph) in which the inserted carbon disulfides act as terminal chelating ligands. These compounds were characterized with ¹H, ¹³C NMR, IR spectroscopy, mass spectrometry, elemental analyses, and X‐ray crystallography.     

The effect of solvent accessible surface on Hammett‐type dependencies of infinite dilution 29Si and 13C NMR shifts in ring substituted silylated phenols dissolved in chloroform and acetone

Infinite dilution ²⁹Si and ¹³C NMR chemical shifts were determined from concentration dependencies of the shifts in dilute chloroform and acetone solutions of para substituted O‐silylated phenols, 4‐R‐C₆H₄‐O‐SiR′₂R″ (R = Me, MeO, H, F, Cl, NMe₂, NH₂, and CF₃), where the silyl part included groups of different sizes: dimethylsilyl (R′ = Me, R″ = H), trimethylsilyl (R′ = R″ = Me), tert‐butyldimethylsilyl (R′ = Me, R″ = CMe₃), and tert‐butyldiphenylsilyl (R′ = C₆H₅, R″ = CMe₃). Dependencies of silicon and C‐1 carbon chemical shifts on Hammett substituent constants are discussed. It is shown that the substituent sensitivity of these chemical shifts is reduced by association with chloroform, the reduction being proportional to the solvent accessible surface of the oxygen atom in the Si‐O‐C link. Copyright © 2012 John Wiley & Sons, Ltd.     

Methyl- and phenyl-bis(tertiary phosphine) N-bonded carboxamido complexes of platinum(II)

Methyl- or phenylN-carboxamido-complexes of platinum(II) Pt(NHCOR')RL₂ (L = PEt₃, R = Me, R′ = Me, CH = CH₂; L = PEt₃, R = Ph, R′ = Me; L = PMe₂Ph, R = Ph, R′ = Me, Ph; L = PMePh₂, R = Ph, R′ =₃, R = Ph, R′ = Me) have been prepared by the reaction of KOH with cationic nitrile complexes [PtR(NCR′)L₂]BF₄. Thermally unstable hydrido-N-carboxamido-complexes could be detected spectroscopically. IR and NMR (¹H, ³¹P) spectra of some of the complexes indicate the existence of a solvent- and temperature-dependent equilibrium between syn-and anti-isomers arising from restricted rotation about the NC bond of the carboxamido-group. The anti-isomer is favoured by nonpolar solvents and by increasing bulk of L. In the complex [PtH(NCCH CH₂)(PEt₃)₂]BF₄, IR and NMR spectra show acrlonitrile to be bound through nitrogen, not through the olefinic CC bond.     

Reactions at the B–B Bond of Bis(trisyl)oxadiborirane: Ring Extensions

The B–B bond of bis(trisyl)oxadiborirane OB₂R₂ (R = C(SiMe₃)₃) is opened by amides R′CO(NHR″) to give the dioxaazadiboracyclohexanes [–BR–O–BR–NR″–CHR′–O–] (R′/R″ = H/H, H/Me, H/Et, Me/H: 5 a – d ). The amide MeCO(NHMe) yields 5 e (R′/R″ = Me/Me), when an excess of the amide is applied for 24 h, but yields an isomeric 1 : 1 adduct ( 6 e ), when a stoichiometric amount of the amide is applied for 15 h; upon refluxing this isomer in hexane, it is transformed into 5 e .     

O-Alkyl Trithiophosphate Derivatives of Triorganotin(IV) and S-Alkyl Trithiophosphate Derivatives of Diorganotin(IV) Chloride

Reactions of triorganotin chlorides with potassium salt of O-alkyl trithiophosphate [ROP(S)(SK)₂; R = Me, Prⁱ, Ph] in 2:1 molar ratio in anhydrous benzene yield triorganotin O-alkyl trithiophosphate of the type ROP(S) [SSnR′₃]₂ R = Me, Prⁱ; Ph, R′ = Prⁿ, Buⁿ, Ph] which are found to be monomeric in nature. These complexes are soluble in common organic solvents. Similar reactions of diorganotin chloride with dipotassium salt of S-alkyl trithiophosphate yield diorganotin-S-alkyl trithiophosphate of the type [(RS)P(O)S₂]₂SnR′₂; R = Me, Prⁱ; R′ = Me, Et, Ph, which also are found to be monomeric in nature and are soluble in common organic solvents. The newly synthesized derivatives have been characterized by physicochemical and spectroscopic techniques, IR, NMR (¹H, ³¹P, and ¹¹⁹Sn).