Synthesis of medium-ring lactones via tandem methylenation/Claisen rearrangement of cyclic carbonates
作者:Edward A Anderson、James E.P Davidson、Justin R Harrison、Paul T O'Sullivan、Jonathan W Burton、Ian Collins、Andrew B Holmes
DOI:10.1016/s0040-4020(02)00049-2
日期:2002.3
vinyl-substituted 6- and 7-membered cyclic carbonates into 8- and 9-membered medium-ringlactones has been achieved in good yield using dimethyltitanocene in toluene at reflux. The reaction proceeds by initial formation of a ketene acetal which undergoes subsequent in situ Claisen rearrangement to provide the corresponding lactones. The preparation of the cyclic carbonates is carried out under basic conditions