title: Asymmetric synthesis of alpha,alpha-difluoro-beta-amino acid derivatives from enantiomerically pure N-tert-butylsulfinimines.
abstract: Addition of the Reformatsky reagent derived from ethyl bromodifluoroacetate to alkyl- and aryl-substituted N-tert-butylsulfinimines furnishes beta-tert-butylsulfinamyl-beta-substituted alpha,alpha-difluoroproponiates in diastereomeric ratios ranging from 80:20 to 95:5. The diastereomers are easily separated and the enantiomerically pure, protected beta-amino esters are readily transformed to the corresponding acid, amide, and amine derivatives as useful synthons for medicinal chemistry targets.
authors.affiliation: Merck Research Laboratories, West Point, Pennsylvania 19486, and Merck Research Laboratories, Rahway, New Jersey 07065, USA. donnette_staas@merck.com
authors.forename: Donnette D
authors.initials: DD
authors.lastname: Staas
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Savage
authors.forename: Carl F
authors.initials: CF
authors.lastname: Homnick
authors.forename: Nancy N
authors.initials: NN
authors.lastname: Tsou
authors.forename: Richard G
authors.initials: RG
authors.lastname: Ball
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis*; D005461:Fluorine; D007097:Imines; D013237:Stereoisomerism; D013449:Sulfonamides / Q000737:chemistry
chemical_list: D000596:Amino Acids; D007097:Imines; D013449:Sulfonamides; C408993:tert-butylsulfonamide; D005461:Fluorine