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