Asymmetric syn-selective aldol reactions of gamma-oxygenated vinylogous urethane with a second generation of chiral auxiliary: application in construction of (+)-3-deoxy-D-manno-2-octulosonic acid

A study was conducted to characterize the aldol reactions of vinylogous urethane with different aldehydes. Some of the transformations analyzed in the study were the hydrolysis of the vinylogous urethane functionality and the stereoselective minimization of the resulting beta-keto-lactone. Experimental results indicated that aggregate nonracemic lithium enolate was the reacting species that supported excellent enantioselectivities.