Chiral 2,5-Dihydrofurans Via Tandem Lipase/Gold Catalysis

Significance

Prior to this study, studies of tandem enzyme/transition-metal-catalyzed reactions were quite rare. The authors report the one-pot tandem lipase [from Burkholderia cepacia (PS Amano SD)] catalyzed kinetic resolution of racemic α-allenic acetates followed by a gold-catalyzed cycloisomerization to afford 2,5-dihydrofurans in good conversions and with excellent ee values. However, substrates with bulky groups at R^² give low conversion as the lipase seems to be sensitive to steric hindrance at this position.