one-pot procedure to achieve efficient DYKAT of α-substituted β-hydroxyketones. This newly developed protocol offers straightforward access to enantiomericallypure and diastereomerically enriched β-oxoacetates in high yields by employing a ruthenium-based racemization catalyst for efficient racemization-epimerization of substrates via formation of non-chiral 1,3-diketone intermediates.
An Alternative Approach to Aldol Reactions: Gold-Catalyzed Formation of Boron Enolates from Alkynes
作者:Cindy Körner、Pavel Starkov、Tom D. Sheppard
DOI:10.1021/ja102129c
日期:2010.5.5
A new method for enolate generation via the gold-catalyzed addition of boronic acids to alkynes is reported. The formation of boron enolates from readily accessible ortho-alkynylbenzeneboronic acids proceeds rapidly with 2 mol % PPh(3)AuNTf(2) at ambient temperature. The enolates undergo aldol reaction with an aldehyde present in the reaction mixture to give cyclic boronate esters, which can be subsequently