Reduktive Co‐Alkylierung von Heptamethyl‐cobyrinat mit dem Methylthiomalonat ( S )‐Methyl‐3‐bromo‐2‐[(ethylthio) carbonyl]‐2‐methylpropanoat

Reductive Co Alkylation of Heptamethyl Cobyrinate with the Methylthiomalonate ( S )‐Methyl 3‐Bromo‐2‐[(ethylthio)carbonyl]‐2‐methylpropanoate The methylthiomalonate(−)‐( S )‐Methyl 3‐bromo‐2‐[(ethylthio)carbonyl]‐2‐methylpropanoate( 5a )was prepared from dimethyl methylmalonate in five steps via the stereospecific cleavage of the ( pro ‐ S )‐ester group of 1 with pig‐liver esterase in an overall yield of 26.5% ( Scheme 4a ). Reductive Co alkylation of heptamethyl Co β‐perchlorato cob (II)yrinate ( 8 ) with 5a by electrosynthesis lead to the alkylcobalt complex 9a in 40% yield ( Scheme 4b). The O2‐dependent reactions of the methyhnalonyl fragment produced by photolysis of 9a and its deuterated derivative 9c are reported ( Scheme 5 ).