Conjugate addition of 2-(bromomethyl)- and 2-(2-bromoethyl)piperidine to alkyl acrylates : application towards the synthesis of 2-(methoxycarbonyl)indolizidine
Conjugate addition of 2-(bromomethyl)- and 2-(2-bromoethyl)piperidine hydrobromide to methyl and ethyl acrylate in the presence of triethylamine afforded the corresponding 3-[2-(bromomethyl)piperidin-1-yl]propanoates and 3-[2-(2-bromoethyl)piperidin-1-yl]propanoates for the first time. Furthermore, methyl 3-[2-(bromomethyl)piperidin-1-yl]propanoate was converted into the novel 2-(methoxycarbonyl)indolizidine upon treatment with lithium diisopropylamide in THF. The latter ester was easily reduced by means of lithium aluminium hydride in diethyl ether, affording 2-(hydroxymethyl)indolizidine in high yield
