Diastereofacial selectivity via aldol reactions using ethyl dithioacetate and ethyl dithiopropionate enolates
作者:A.I. Meyers、Robert D. Walkup
DOI:10.1016/s0040-4020(01)96754-7
日期:1985.1
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
二硫代乙酸乙酯的烯醇锂与α-甲基醛反应生成醛醇产物,其中相对于抗构象,在产物的硫代羰基的β和γ位的顺式构象更有利。该选择性取决于溶剂,并且在较低的温度下会提高。在大多数情况下,根据α-甲基醛的结构,在这些条件下获得的顺式:反式产物比率从57:43到> 99:1不等。当使二硫代丙酸乙酯的烯醇锂与α-甲基醛反应时,在产物混合物中仅检测到四种可能的非对映异构体中的两种。