title: Lewis acid/base catalyzed [2+2]-cycloaddition of sulfenes and aldehydes: a versatile entry to chiral sulfonyl and sulfinyl derivatives.
abstract: The first catalytic asymmetric synthesis of β-sultones is reported. This development has enabled a rapid access to a number of highly enantioenriched biologically interesting sulfonyl and sulfinyl compound classes, which makes use of the inherent ring strain of the four-membered heterocycles. The products possess either two vicinal stereocenters, such as in β-hydroxy-sulfonamides, -sulfonates, -sulfones, -sulfonic acids, -sulfinic acids, γ-sultines, and γ-sultones or a single stereocenter, such as in α-branched alkyl or allyl sulfonic acids. This work also represents the first application of sulfene intermediates in asymmetric catalysis. The reactivity of a sulfene normally acting as an electrophile could be reverted by the formation of a nucleophilic zwitterionic sulfene-amine adduct. To achieve a combination of high enantioselectivity and reactivity, cooperative catalytic action of a chiral nucleophilic tertiary amine (the cinchona alkaloid derivative diydroquinine 2,5-diphenyl-4,6-pyrimidinediyl diether ((DHQ)(2)PYR)) and Bi(OTf)(3) or In(OTf)(3) was of primary importance.
authors.affiliation: ETH Zürich, Laboratory of Organic Chemistry, Wolfgang-Pauli-Str. 10, 8093 Zürich, Switzerland.
authors.forename: Florian M
authors.initials: FM
authors.lastname: Koch
authors.forename: René
authors.initials: R
authors.lastname: Peters
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D002384:Catalysis; D058116:Lewis Acids / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism; D013416:Sulfamerazine / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013450:Sulfones / Q000737:chemistry*
chemical_list: D000447:Aldehydes; D058116:Lewis Acids; D013438:Sulfhydryl Compounds; D013450:Sulfones; C012049:sulfaperine; D013416:Sulfamerazine