Syntheses relevant to vitamin B12biosynthesis: the glutamate route to (–)-ring-B imide and synthesis of the 2,7,12,20-tetramethylisobacteriochlorin
Abstract
An enantioselective synthesis of (–)-ring-B imide (19) from inexpensive glutamic acid is described and the product is used for synthesis of the 2,7,12,20-tetramethylisobacteriochlorin (39) required for future transformation into later biosynthetic intermediates for vitamin B12.