title: Asymmetric modular synthesis of highly functionalized medium-sized carbocycles and lactones via ring-closing metathesis of sulfoximine-substituted trienes.
abstract: A modular asymmetric synthesis of medium-sized carbocycles and lactones has been developed that affords highly substituted 7-, 9-, and 11-membered rings. The key steps are (1) the highly diastereoselective synthesis of sulfoximine-substituted homoallylic alcohols from allylic sulfoximines and unsaturated as well as saturated aldehydes, (2) an E-stereoselective alkylation and hydroxyalkylation of sulfoximine-substituted alkenyllithium derivatives, (3) the esterification of sulfoximine-substituted homoallylic alcohols, and (4) the ring-closing metathesis reaction of sulfoximine-substituted trienes with the ruthenium catalyst 8. Two examples for the further synthetic elaboration of the sulfoximine-substituted carbocycles are provided. The selective cleavage of the tert-butyldimethylsilyl group of 12 in the presence of the triethylsilyl group afforded the allylic alcohol 18 which was oxidized to enone 19. A cross-coupling reaction of the sulfoximine-substituted carbocycle 9 with LiCuMe2 furnished the methyl-substituted derivative 20.
authors.affiliation: Institut für Organische Chemie, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen, Landoltweg 1, 52056 Aachen, Germany.
authors.forename: Michal
authors.initials: M
authors.lastname: Lejkowski
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Gais
authors.forename: Prabal
authors.initials: P
authors.lastname: Banerjee
authors.forename: Cornelia
authors.initials: C
authors.lastname: Vermeeren