Open AccessIndução assimétrica 1,5-Anti na adição de enolatos de boro de metilcetonas beta-oxigenadas a aldeídos
Author(s) -
Luiz C. Dias,
Andrea M. Aguilar
Publication year - 2007
Publication title -
química nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.214
H-Index - 73
eISSN - 1678-7064
pISSN - 0100-4042
DOI - 10.1590/s0100-40422007000800036
Subject(s) - aldol reaction , boron , adduct , chemistry , selectivity , alkoxy group , substrate (aquarium) , stereochemistry , boro , hydrogen , medicinal chemistry , organic chemistry , catalysis , biology , ecology , alkyl
High levels of substrate-based 1,5-stereoinduction are obtained in the boron-mediated aldol reactions of beta-oxygenated methyl ketones with achiral and chiral aldehydes. Remote induction from the boron enolates gives the 1,5-anti adducts, with the enolate pi-facial selectivity critically dependent upon the nature of the beta-alkoxy protecting group. This 1,5-anti aldol methodology has been strategically employed in the total synthesis of several natural products. At present, the origin of the high level of 1,5-anti induction obtained with the boron enolates is unclear, although a model based on a hydrogen bonding between the alkoxy oxygen and the formyl hydrogen has been recently proposed