A catalytic asymmetric synthesis of the a-methylene lactones starting with the prochiral alkenyl halides 8 and 19 has been achieved for the first time, giving 9 in 57% enantiomeric excess (erne.) and 20 in 39% ee, respectively. ... Metal complex catalysed carbonylation reactions offer useful methods for the syntheses of carboxylic acids, esters, amides, aldehydes etc., and these methods are of considerable industrial value. However, application of a carbonylation ...
