Synthesis of Four Stereoisomers of (<i>S</i>)-2-Methylpent-3-yl 3,13-Dimethylpentadecanoate, a Sex Pheromone of the Bagworm Moth<i>Clania variegate</i>, Using Stereospecific Inversion of Secondary Sulfonates as a Key Step
Recently, we have established a simple preparative method for the synthesis of methyl-branched building blocks by utilizing an SN2reaction of chiral secondary tosylates derived from (S)- and (R)-propylene oxides. The usefulness of these building blocks was demonstrated by their application in the synthesis of all four stereoisomers of an acid moiety in the bagworm pheromone. The enantiomeric purities of
Enantiomerically pure triflones R1CH(R2)SO2CF3 have been synthesized starting from the corresponding chiral alcohols via thiols and trifluoromethylsulfanes. Key steps of the syntheses of the sulfanes are the photochemical trifluoromethylation of the thiols with CF3Hal (Hal=halide) or substitution of alkoxyphosphinediamines with CF3SSCF3. The deprotonation of RCH(Me)SO2CF3 (R=CH2Ph, iHex) with nBuLi
Abstract Mechanism of a novel transformation of the alkyl phenyltellurides to alkyl halides via nucleophilic substitution of the phenyltelluro group in organotelluriums is studied on the basis of kinetics and stereochemistry using the titled chiral substrate. The results obtained strongly suggest that the substitutions proceed via SN2 mechanism with Walden inversion and very low Arrhenius' energies
Inversion of secondary chiral alcohols in toluene with the tunable complex of R3NR′COOH
作者:Xiao-Xin Shi、Chun-Li Shen、Jian-Zhong Yao、Liang-Deng Nie、Na Quan
DOI:10.1016/j.tetasy.2009.12.028
日期:2010.3
The S(N)2 reaction of enantiomerically pure sulfonates with the tunable complex of R3N-R'COOH in toluene has been extensively studied. It was revealed that the molar ratio of the tertiary amines and carboxylic acids in the complex of R3NR'COOH is crucial for the S(N)2 reaction, and should be tuned for each sulfonate to give the best yield. Fifteen sulfonates 1 and 3-13 (Scheme 2) were prepared and transformed into 22 corresponding inverted esters 2 and 14-24 (Scheme 2) in good to high yields. (C) 2010 Elsevier Ltd. All rights reserved.
Kenyon; Phillips; Pittman, Journal of the Chemical Society, 1935, p. 1079