Enantiomerically pure ring building block for naturally occurring hydroporphyrins and possibly vitamin B12 was synthesized starting from methylated Hagemann´s ester. Originally, this ester was utilized to investigate preparation of ring building blocks for vitamin B12 in Eschenmoser´s and Woodward´s syntheses. Hagemann´s ester furnished methyl 4-acetoxy-2,3-dimethylcyclohex-2-en-1-carboxylate in racemic form. Kinetic enzymatic resolution of the cyclohexene acetate led to the enantiopure hydroporphyrin building block methyl {(1S,2S,5S,3Z)-3-(2-t-butoxy-2-oxoethylidene)-1. 5-dimethyl-7-oxo-4-aza-6-oxabicyclo[3.3.0]oct-2-yl}-2-propionate. O CO 2 CH 3 CO 2 CH 3 OH N H O CO 2 CH 3 O CO 2 tBu CO 2 CH 3 OAc
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.