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Chemoselective Additions of Chloromethyllithium Carbenoid to Cyclic Enones: A Direct Access to Chloromethyl Allylic Alcohols
Author(s) -
Pace Vittorio,
Castoldi Laura,
Holzer Wolfgang
Publication year - 2014
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201301042
Subject(s) - carbenoid , chemistry , allylic rearrangement , cyclopropanation , heteroatom , reagent , conjugate , medicinal chemistry , lewis acids and bases , organic chemistry , catalysis , rhodium , ring (chemistry) , mathematical analysis , mathematics
Chloromethyllithium carbenoid has been chemoselectively added to cyclic enones (5‐, 6‐ and 7‐membered systems, including two natural products) to provide chloromethyl allylic alcohols. Under the optimized reaction conditions neither concomitant ( n+1 ) homologation nor conjugate addition or Simmons–Smith‐like cyclopropanation takes place. The presence of LiBr is estimated to play a dual role, namely as a carbenoid stabilizer and mild Lewis acid activator of the CO group. Notably, the mesomeric effect caused by β‐heteroatom‐containing substituents promotes the attack of the reagent at the most activated position.