Asymmetric synthesis of bicyclic beta-lactones via the intramolecular, nucleophile-catalyzed aldol lactonization: improved efficiency and expanded scope.
[reaction: see text] The intramolecular, nucleophile-catalyzed, aldol lactonization (NCAL) process merges catalytic, asymmetric carbocycle synthesis with beta-lactone synthesis. The application of modified Mukaiyama reagents to this process led to greatly improved conversion and efficiency (70-82% yield) and shorter reaction times with no diminution of enantioselectivity (91-98% ee). The process was extended to several new aldehyde-acid substrates leading to new bicyclic-beta-lactones. This methodology uniquely provides beta-lactone-fused cyclopentanes and cyclohexanes readied for further transformations.
Oh
Seong Ho
SH
Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, USA.
Cortez
Guillermo S
GS
Romo
Daniel
D
D007783:Lactones / Q000138:chemical synthesis* / Q000737:chemistry
D007783:Lactones