Imran Ahmad, Vinay Pathak, Prema G Vasudev, Hardesh K. Maurya and Atul Gupta
RSC Adv. 2014, 4, 24619
Accepted 12 May 2014
First published online 13 May 2014
Abstract
Borontribromide (BBr3) is a well known demethylating agent. Current investigation was focused on a new application of borontribromide as C-C bond forming agent in cyclic ketones. In this study, borontribromide mediated C-C bond formation reactions of tetralones, chromenone, thiochromenone and indanones were explored. Methoxy group containing ketones showed selective C-C bond formation reaction instead of demethylation of methoxy group. MM2 steric energy calculations for final products showed that reaction favored the formation of exo or endo cyclic double bond containing products depending upon their low MM2 steric energy in a specific frame structure as observed in x-ray crystallography. A comprehensive crystallographic and pi-stacking analysis of product 10a exhibited the formation of 10a as enantiomeric mixture and its centre of inversion was stabilized by a set of three unique pi-pi interactions.
