DIASTEREOFACIAL SELECTIVITY VIA ALDOL REACTIONS USING ETHYL DITHIOACETATE AND ETHYL DITHIOPROPIONATE ENOLATES

Article abstract of DOI:10.1016/S0040-4020(01)96754-7

The lithium enolate of ethyl dithioacetate reacts with α-methyl aldehydes to yield the aldol products in which the syn configuration in the positions β and γ to the thiocarbonyl of the product is favored over the anti configuration.This selectivity is solvent-dependent, and is enhanced at lower temperatures.In most cases, syn:anti product ratios obtained under these conditions varied from 57:43 to >99:1, depending upon the structure of the α-methyl aldehyde.When the lithium enolate of ethyl dithiopropionate was allowed to react with α-methyl aldehydes, only two out of the four possible diastereomers were detected in the product mixtures.