New Mixed Phosphonate Esters by Transesterification of Pinacol Phosphonates and Their Use in Aldehyde and Ketone Coupling Reactions with Nonstabilized Phosphonates
作者:John F. Reichwein、Brian L. Pagenkopf
DOI:10.1021/jo026834c
日期:2003.2.1
and alkylation with aldehydes or ketones gave beta-hydroxy mixed phosphonate esters. tert-Butyl and benzylic phosphonate ester protective groups were introduced to improve the efficiency and functional group compatibility of beta-hydroxy phosphonate saponification. The beta-hydroxy phosphonic acid monomethyl esters were dehydrated with diisopropylcarbodiimide, which gave oxaphosphetane intermediates
通过铑催化的烯烃加氢磷酸化制备烷基炔醇膦酸酯,并尝试将频哪醇衍生的烷基膦酸酯的α-去质子化导致环裂解。利用烷基频哪醇膦酸酯的开环倾向,通过在酸化的甲醇中进行酯交换反应来高产率地制备膦酸单甲酯。用醛或酮进行酯化和烷基化,得到β-羟基混合的膦酸酯。引入叔丁基和苄基膦酸酯保护基以提高β-羟基膦酸酯皂化的效率和官能团相容性。用二异丙基碳二亚胺使β-羟基膦酸单甲酯脱水,从而得到氧杂磷杂环戊烷中间体,该中间体坍塌为烯烃。