Regioselective palladium-catalyzed ring-opening reactions of C1-substituted oxabicyclo[2,2,1]hepta-2,5-diene-2,3-dicarboxylates

Abstract

SummaryPalladium-catalyzed ring-opening reactions of C1 substituted 7-oxanorbornadiene derivatives with aryl iodides were investigated. The optimal conditions for this reaction were found to be PdCl2(PPh3)2, ZnCl2, Et3N and Zn in THF. Both steric and electronic factors played a role in the outcome of the reaction as increasing the steric bulk on the bridgehead carbon decreased the yield. These reactions were found to be highly regioselective, giving only one of the two possible regioisomers in all cases. A diverse collection of novel, highly substituted biphenyl derivatives were obtained.

[(1R*,3S*,4S*)-3-(2-Hydroxybenzoyl)-1,2,3,4-tetrahydro-1,4-epoxynaphthalen-1-yl]methyl 4-nitrobenzoate

“…In past years, our research group (Ballantine et al, 2009;Edmunds et al, 2015;Hill & Tam, 2019;Edmunds et al, 2016;Raheem et al, 2014) has investigated the effects of various C 1 -substituted oxabenzonorbornadienes (OBD) on controlling the regioselectivity of ring-opening reactions. In 2015, Nagamoto and Nishimura reported the iridiumcatalysed hydroacylation reaction of bicyclic alkenes with 2-hydroxybenzaldehyde and its derivatives.…”

1-[(1R*,2R*)-1,2-Dihydroxy-1,2-dihydronaphthalen-1-yl]ethan-1-one

“…In past years, our research group has investigated the effects of various C 1 -substituted oxabenzonorbornadienes (OBDs) on controlling the regioselectivity of ring-opening reactions (Ballantine et al, 2009;Edmunds et al, 2015Edmunds et al, , 2016Raheem et al, 2014). Very recently, Yang et al (2019) reported the first iridium-catalysed ring-opening reaction of oxa/aza benzonorbornadienes with various alcohol nucleophiles.…”