Total syntheses of (.+-.)-cephalotaxine and (.+-.)-8-oxocephalotaxine

ME Kuehne, WG Bornmann, WH Parsons…

Index: Kuehne; Bornmann; Parsons; Spitzer; Blount; Zubieta Journal of Organic Chemistry, 1988 ,  vol. 53,  # 15  p. 3439 - 3450

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Citation Number: 64

Abstract

A synthesis of (A)-cephalotaxine (1) was obtained based on a novel oxidative rearrangement of the bicyclic enamide 5 to the spirocyclopentanone lactam 20. The overall yield from keto ester 6 and amine 7 was 28%, in nine steps, or 41% in ten steps. Double- bond isomerization of minor side product ene lactam 9, with formation of the key ene lactam intermediate 5, increased the overall yields of the synthesis to 45%(nine steps) or 66%(ten ...