title: Synthesis of stereoisomeric medium-ring alpha,alpha'-dihydroxy cycloalkanones.
abstract: The stereochemical course of the epoxidation of the silyl enol ethers of 2-tert-butyldimethylsilyloxycycloheptanone and -cyclooctanone has been investigated and shown to proceed exclusively anti to the existing alpha-substituent. 2-(Benzyloxy)cyclooctanone behaves similarly, and the presence of a transannular double bond does not alter the outcome. Alpha-ketol rearrangements are seen to operate during ensuing fluoride ion-induced removal of the silyl protecting groups in select examples. The preferred means for generating the cis isomers of the alpha,alpha'-dihydroxy cycloalkanones involves methylenation of the monoprotected trans-dihydroxy ketones with the Nysted reagent, followed by oxidation and subsequent reduction with sodium borohydride. Ozonolysis and fluoride ion-induced desilylation complete the route.
authors.affiliation: Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA. paquette.1@osu.edu
authors.forename: Leo A
authors.initials: LA
authors.lastname: Paquette
authors.forename: Ryan E
authors.initials: RE
authors.lastname: Hartung
authors.forename: John E
authors.initials: JE
authors.lastname: Hofferberth
authors.forename: Ivan
authors.initials: I
authors.lastname: Vilotijevic
authors.forename: Jiong
authors.initials: J
authors.lastname: Yang