An improved and efficient electrochemical N-acylation of chiraloxazolidin-2-ones has been achieved. The generation of the nitrogen anion is obtained under mild conditions and without addition of base or probase, by direct electrolysis of a solution of MeCN-TEAP containing the oxazolidinone. Acylation agents (acid chlorides or anhydrides) were added at the end of the electrolysis. N-Acylated products
Practical Formal Total Syntheses of the Homocamptothecin Derivative and Anticancer Agent Diflomotecan via Asymmetric Acetate Aldol Additions to Pyridine Ketone Substrates
scalable asymmetric routes to DE ring fragment 7, a key building block in the synthesis of the homocamptothecin derivative diflomotecan 4, are described. The “acetal route” starts from 2-chloro-4-cyanopyridine 8 and represents an enantioselective and optimized modification of the original racemic discovery chemistry synthesis. The inefficient optical resolution procedure was replaced by an efficient asymmetric