Practical formal total syntheses of the homocamptothecin derivative and anticancer agent diflomotecan via asymmetric acetate aldol additions to pyridine ketone …

R Peters, M Althaus, C Diolez, A Rolland…

Index: Peters, Rene; Althaus, Martin; Diolez, Christian; Rolland, Alain; Manginot, Eric; Veyrat, Marc Journal of Organic Chemistry, 2006 , vol. 71, # 20 p. 7583 - 7595

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Citation Number: 22

Abstract

Two practical, efficient, and 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 acetate ...