Synlett

New synthesis of a pyrroloquinoline skeleton, the Martinelline core, using a tandem Michael-aldol strategy

O Hara, K Sugimoto, K Makino, Y Hamada

Index: Hara, Osamu; Sugimoto, Kazuhiko; Makino, Kazuishi; Hamada, Yasumasa Synlett, 2004 , # 9 p. 1625 - 1627

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Citation Number: 17

Abstract

Our synthesis was started with preparation of Michael acceptor 9 (Scheme [2] ). Commercially available cyano acetal 7 was exposed to toluenesulfonic acid under refluxing conditions for 2 hours and the resulting aldehyde was treated with acetone in the presence of a catalytic amount of (S)-proline. [5] The aldol condensation proceeded cleanly to give aldol 8 and dehydrated 9 in 71% and 21% yields, respectively. The aldol was efficiently converted to the desired 9 ...