Synthesis of γ-Acetoxy β-Keto Esters Through Regioselective Hydration of γ-Acetoxy-α,β-alkynoates
作者:Tapas R. Pradhan、Kishor L. Mendhekar、Debendra K. Mohapatra
DOI:10.1021/acs.joc.5b00400
日期:2015.6.5
The At(I)-catalyzed regioselective hydration of gamma-acetoxy-alpha,beta-acetylinic ester by the assistance of a neighboring carbonyl group has beets developed. Varieties of simple primary, secondary, and tertiary gamma-acetoxy-alpha,beta-acetylinic esters, even those bearing sensitive functional group in the remote reaction sites, are selectively hydrated to the corresponding beta-keto esters. The reaction' tolerates a wide variety of other carboxylates, such as benzoates, propionates, acrylates, and pivalates, including chiral carboxylates with retention of the configuration. The broad substrate scope, including the derivatization of complex natural products and neutral and open air conditions, makes this atom economical approach very practical. O-18 labeling experiments disclose that the oxygen transposition occurs from the carboxylate group to the triple bond, not from water.