Nonreductive Enantioselective Ring Opening of<i>N</i>-(Methylsulfonyl)dicarboximides with Diisopropoxytitanium α,α,α′,α′-Tetraaryl-1,3-dioxolane-4,5-dimethanolate
作者:Diego J. Ramón、Gabriela Guillena、Dieter Seebach
DOI:10.1002/hlca.19960790328
日期:1996.5.8
dicarboximides 1a–f are converted enantioselectively to isopropyl [(sulfonamido)carbonyl]-carboxylates 2a–f by diisopropoxytitaniumTADDOLate (75–92% yield; see Scheme 3). The enantiomer ratios of the products are between 86:14 and 97:3, and recrystallization from CH2Cl2/hexane leads to enantiomerically pure sulfonamido esters 2 (Scheme 3). The enantioselectivity shows a linear relationship with the