A new twist: The catalytic asymmetric semipinacol rearrangement reaction of 2‐oxo allylic alcohols 1 in the presence of a catalytic amount of chiral phosphoric acid (R)‐2 a or its silver salt (R)‐2 b affords enantiomerically pure spiroethers 3.
Organocatalytic Asymmetric Fluorination/Semipinacol Rearrangement: An Efficient Approach to Chiral β-Fluoroketones
作者:Zhi-Min Chen、Bin-Miao Yang、Zhi-Hua Chen、Qing-Wei Zhang、Min Wang、Yong-Qiang Tu
DOI:10.1002/chem.201202444
日期:2012.10.8
An asymmetricfluorination/semipinacol rearrangement of 2‐oxa allylic alcohols, as catalyzed by cinchona‐alkaloid derivatives, gives chiral β‐fluoro ketones with moderate to high levels of enantioselectivity (see scheme). Both enantiomers of the product could be obtained by using the appropriate catalyst.