Convenient synthesis of optically active deuterated primary alcohols via deuteride reduction of acetals derived from homochiral (1R∗,2R∗)-3,3,3-trifluoro-1-phenylpropane-1,2-diols
作者:Carlo F. Morelli、Paola Cairoli、Tiziana Marigolo、Giovanna Speranza、Paolo Manitto
DOI:10.1016/j.tetasy.2009.01.020
日期:2009.2
(1R)-1-Deuterated alcohols with high enantiomeric excess were prepared via TiCl4/Et3SiD reduction of acetals arising from the reaction of aldehydes with (1S,2S)-3,3,3-trifluoro-1-phenylpropane-1,2-diol 9. Such a chiral auxiliary was synthesized in an enantiomerically pure form starting from L-mandelic acid. Due to its benzylic nature, it was easily removed from the reaction product of the reductive 1,3-dioxolane ring-cleavage to afford the desired alpha-deuterated alcohol. (C) 2009 Elsevier Ltd. All rights reserved.
A new chiral catalyst for the enantioselective synthesis of secondary alcohols and deuterated primary alcohols by carbonyl reduction
作者:E.J. Corey、John O. Link
DOI:10.1016/s0040-4039(01)93871-7
日期:1989.1
efficient synthesis of(S)-(−)-2-(di-β-naphthylhydroxymethyl)pyrrolidine (1) makes available the oxazaborolidine derivatives2 and3 which are excellent catalysts for borane reduction of a variety of achiral ketones to chiral secondary alcohols, e.g. acetophenone, 98% ee; α-tetralone, 95% ee; and methyl-4-oxo-4-phenyl butyrate, 96% ee. The synthesis of chiral 1-deuterio primary alcohols fromachiral aldehydes
Stereoselective TiCl<sub>4</sub>-Promoted Nucleophilic Substitution at C-2 of (4<i>S</i>,5<i>S</i>)-2-Alkyl-4-methyl-5-trifluoromethyl-1,3-dioxolanes
作者:Carlo F. Morelli、Lavinia Durì、Alberto Saladino、Giovanna Speranza、Paolo Manitto
DOI:10.1055/s-2004-834884
日期:——
ring-opening reactions of chiral acetals derived from (2S,3S)-1,1,1-trifluorobutane-2,3-diol proceed in a completely regioselective manner, leading to the break of the O1-C2 bond accompanied by a high degree of stereoselectivity. The use of triethylsilyl deuteride or allyltributyltin as nucleophiles gives access, after removal of the chiral auxiliary, to stereoselectively deuterated primaryalcohols or homoallylic
Configurational Stability of Oxymethyllithiums as Intermediates in Intramolecular Rearrangements
作者:Dagmar C. Kapeller、Lothar Brecker、Friedrich Hammerschmidt
DOI:10.1002/chem.200701054
日期:2007.11.26
were tested for their microscopic configurational stability in intramolecular isomerizations, such as the silyl- and germyl-[1,2]-retro-Brook and the sigmatropic[2,3]-Wittig rearrangement. The influence of temperature, solvent, and migrating group on the stability of the intermediate carbanions was studied. Furthermore, the stereochemical course of these rearrangements was elucidated, resulting in highly
Micellar effects in the nitrous acid deamination reaction of (R)-[1-2H]-1-octanamine
作者:Daniel Brosch、Wolfgang Kirmse
DOI:10.1021/jo00057a025
日期:1993.2
The nitrous acid deamination of 1-octanamine (1) afforded mixtures of isomeric octenes, octanols, and octyl nitrites. The aggregation of 1.HClO4 in micelles induced the formation of dioctyl ethers and of 1-nitrooctane as additional products. In homogeneous solution (submicellar aqueous conditions or HOAc), [1-H-2]-1-octanol was obtained from [1-H-2]-1 with ca. 95% inversion of configuration. Above the critical micelle concentration, the enantiomeric purity of [1-H-2]-1-octanol decreased while [1-H-2]-1-nitrooctane was formed with ca.90% retention of configuration. 1-Octyl..NO2 radical pairs, rather than ion pairs, are likely to intervene on the retentive route to 1-nitrooctane and 1-octyl nitrite. Equilibration, via NO exchange, of (R)-[1-H-2]-1-octyl nitrite with the more abundant (S)-[1-H-2]-1-octanol is thought to account for the diminished ee of both products.