ABSTRACT
It has been reported that gamma, gamma-diary l-gamma-butyrolactones have chemo-therapeutic activity on pathogenic viruses. This reported activity coupled with our interest in the chemistry of butyrolactones prompted us to report a convenient method for the synthesis of gamma, gamma-diary l-gamma-butyrolactones [VI alpha-c] This method involves ring opening of the diarylethylene oxide [la-c] followed by ring closure [a/, scheme. 1]. Hydrolysis of the products followed: by decarboxylation give gamma, gamma-diary l-gamma-butyrolactones in a better yield than their synthesis via stobbe condensation method .When ethyl chloroacetone is allowed to react with aryl magnesium-halides [Ar= Ph-,PhCH[2]-,m-tolyl], followed by dehydrohalogenation, 1,1-diarylethylene oxides [la-c] are formed
ABSTRACT
It is worth mention to report from the present investigation and HMO calculations that the steric factors play a significant role in controlling the rate of dibromocarbene addition to tri- and tetra-aryl substituted ethylenes [1IOTA -P], a point which far too long lacked emphasis in the literature. Although, occasional references to steric hindrance in carbene addition have been reported but nevertheless, emphasis is more generally placed on electronic effects