S,O-acetals as novel "chiral aldehyde" equivalents.
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.
Trost
Barry M
BM
Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA. bmtrost@stanford.edu
Crawley
Matthew L
ML
Lee
Chul Bom
CB
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
D000080:Acetals; D000447:Aldehydes; D013441:Sulfinic Acids; D013450:Sulfones; D010165:Palladium; C425152:benzenesulfinic acid