Arylthio-Metal Exchange of α-Arylthioalkanenitriles
摘要:
The addition of BuLi, Bu3MgLi, Et2ZnBuLi, or Me2CuLi to alpha-arylthioalkanenitriles triggers an arylthio-metal exchange. NMR spectroscopic analyses implicate organometallic attack on sulfur forming a three-coordinate sulfidate as the key intermediate. Electrophilic trapping affords tertiary and quaternary nitriles in high yield. The method addresses the challenge of improving the functional group tolerance and preventing polyalkylations.
Chemoselective Alkylations with <i>N</i>- and <i>C</i>-Metalated Nitriles
作者:Xun Yang、Dinesh Nath、Fraser F. Fleming
DOI:10.1021/acs.orglett.5b02481
日期:2015.10.2
electrophilic alkylations. N-Lithiated or C-magnesiated nitriles can be prepared from the same nitrile precursor and selectively reacted with a 1:1 mixture of methyl cyanoformate and benzyl bromide or bifunctionalelectrophiles through chemoselective attack onto either an alkyl halide or a carbonyl electrophile. A mechanistic explanation for the chemoselectivity preferences is provided that rests on the structural
organolithiums, Grignardreagents, or zincates to sulfinylnitriles triggers a facile sulfinyl–metal exchange to afford N‐ or C‐metalated nitriles. Sulfinyl–magnesium exchange–alkylations efficiently install quaternary and tertiary centers, even in the case of tertiary sulfinylnitriles that contain a highly acidic methine proton. α‐Sulfinylalkenenitriles afford moderately nucleophilic magnesiated nitriles, and