Ammonium-directed dihydroxylation of 3-aminocyclohex-1-enes: development of a metal-free dihydroxylation protocol.
Treatment of 3-aminocyclohex-1-enes with mCPBA in the presence of trichloroacetic acid gives the corresponding 1,2-anti-2,3-syn-1-trichloroacetoxy-2-hydroxy-3-aminocyclohexane with high levels of diastereoselectivity (90% de). This is consistent with a mechanism of oxidation involving hydrogen-bonded delivery of the oxidant by the allylic ammonium ion formed in situ, followed by highly regioselective ring-opening of the intermediate epoxide by trichloroacetic acid. The effect of conformational constraints upon the oxidation reaction is also examined.
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
Caroline
C
Aciro
Timothy D W
TD
Claridge
Stephen G
SG
Davies
Paul M
PM
Roberts
Angela J
AJ
Russell
James E
JE
Thomson
D000588:Amines / Q000737:chemistry; D053138:Cyclohexenes / Q000737:chemistry*; D006878:Hydroxides / Q000737:chemistry*; D006900:Hydroxylation; D008670:Metals / Q000737:chemistry; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity
D000588:Amines; D053138:Cyclohexenes; D006878:Hydroxides; D008670:Metals; D000644:Quaternary Ammonium Compounds; C052568:cyclohexene; C031356:hydroxide ion