title: S,O-acetals as novel "chiral aldehyde" equivalents.
abstract: Palladium-catalyzed asymmetric allylic alkylations (AAA) to form "chiral aldehyde" equivalents were investigated. Alpha-acetoxysulfones were formed in high enantiomeric excess as single regioisomers in AAA reactions of allylic geminal dicarboxylates with sodium benzenesulfinate. The directing ability of this novel functional group was highlighted by a series of dihydroxylations, affording syn diols exclusively anti to the acetoxy sulfone as single diastereomers in excellent yields. This is the first example of an asymmetric dihydroxylation protocol that gives the equivalent of reaction with a simple enal. The synthetic value of this process was exemplified by subsequent transformations of the diols including the development of a one-pot dihydroxylation-deprotective acyl migration protocol to give differentially protected 1,2-diols.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA. bmtrost@stanford.edu
authors.forename: Barry M
authors.initials: BM
authors.lastname: Trost
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Crawley
authors.forename: Chul Bom
authors.initials: CB
authors.lastname: Lee
mesh_terms: D000080:Acetals / Q000737:chemistry*; D000447:Aldehydes / Q000737:chemistry; D000478:Alkylation; D002384:Catalysis; D006900:Hydroxylation; D008968:Molecular Conformation; D010165:Palladium / Q000737:chemistry; D013237:Stereoisomerism; D013441:Sulfinic Acids / Q000737:chemistry; D013450:Sulfones / Q000737:chemistry
chemical_list: D000080:Acetals; D000447:Aldehydes; D013441:Sulfinic Acids; D013450:Sulfones; D010165:Palladium; C425152:benzenesulfinic acid