A glycal based approach to the synthesis of (+)-bulgecinine, 3-hydroxy-2,5-dihydroxymethylpyrrolidine and 2-oxapyrrolizidin-3-one

Abstract

A glycal based synthesis of (+)-bulgecinine, 3-hydroxy-2,5-dihydroxymethylpyrrolidine and 2-oxapyrrolizidin-3-ones proceeding through a common intermediate is reported. The key step in the work presented here is a two-step conversion of 4,6-di-O-benzyl-d-glucal to 2,3-dideoxy-2-tosylamido-d-glucose. This manuscript reports the first carbohydrate based approach to the synthesis of (+)-bulgecinine and the whole sequence has been accomplished with complete stereochemical integrity without the formation of mixture of products in any of these steps.

Keywords: Bulgecinine; Glycal; Glycosidase inhibitors; Natural product; Pyrrolizidine.