title: Synthesis and application of easily recyclable thiomorpholines for use in sulfur ylide mediated asymmetric epoxidation of aldehydes.
abstract: Chiral nonracemic thiomorpholines have been synthesized in four to six steps from limonene or achiral alkenes using alpha-methylbenzylamine to control absolute stereochemistry. These aminosulfides have been used to generate sulfur ylides, which have been applied in the asymmetric epoxidation of aldehydes as easily recoverable catalysts. Excellent yields (up to 98 %), enantioselectivities (up to 97:3 e.r.), and diastereoselectivities (>or=98:2 trans/cis) were achieved in these epoxidations and the sulfides were easily recovered in high yield (up to 97 %) by simple acid/base extraction.
authors.affiliation: School of Chemistry, University of Bristol, Cantock's Close, UK.
authors.forename: Markus
authors.initials: M
authors.lastname: Hansch
authors.forename: Ona
authors.initials: O
authors.lastname: Illa
authors.forename: Eoghan M
authors.initials: EM
authors.lastname: McGarrigle
authors.forename: Varinder K
authors.initials: VK
authors.lastname: Aggarwal