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.
Aciro
Caroline
C
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
Claridge
Timothy D W
TD
Davies
Stephen G
SG
Roberts
Paul M
PM
Russell
Angela J
AJ
Thomson
James E
JE
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