Stereoselective Synthesis of Enantiopure Oxetanes, a Carbohydrate Mimic, an ϵ-Lactone, and Cyclitols from Biocatalytically Derived β-Hydroxy Esters as Chiral Precursors
Biocatalyticallyderivedenantiopure α-substituted β-hydroxyesters serve as excellent chirons for the synthesis of a diverse set of structures such as oxetanes, a carbohydratemimic, an ϵ-lactone, and carbocyclic and aromatic cyclitols. The starting materials can be easily accessed in enantiopure form from α-substituted β-keto esters by biocatalytic reduction with Klebsiella pneumoniae (NBRC 3319)
Diastereoselective Reactions of δ-Oxy-Substituted Allylic Acetates with Organocopper Reagents
作者:Jennifer L. Belelie、J. Michael Chong
DOI:10.1021/jo016310x
日期:2002.5.1
S(N)2' (gamma) substitutions of delta-substituted allylicacetates with Grignard reagents and copper catalysts proceed with high diastereoselectivities. With benzyloxy, methoxymethoxy, and tert-butyldimethylsiloxy groups, reactions favor the anti-isomer with selectivities up to anti:syn = >99:1. With a hydroxyl group, selectivities are reversed and the syn-isomer is favored with selectivities up to