Synthesis of an Optically Active Tricyclic Intermediate for Manzamines

L-Serine has been converted into a chiral pyrrolo[2,3-psoquinoline derivative which can serve as a potential intermediate for manzamines.In a recent communication we have presented a strategy for the synthesis of the tricyclic pyrrolo(2.3-ijisoquinolinesystem (1 a)', which represents the ABC substructure of the manzamine alkaloids3 and, in addition, carries functional groups, which hold potential for the construction of the pcarboline and the thirteen-membered ring of our first synthetic target, namely, the alkaloid manzamine-A (2).Another approach to the parent decahydropyrrolo[2.3-i]isoquinolinesystem has recently been reported by art.^ ln this communication we describe the application of our strategy for the preparation of optically active tricyclic intermediate 1 b.It should be emphasized at the outset that the 5S,lOS,26R # Dedicated to the memory of Professor Telsuji Kametani; a dedicated and inspiring chemist and a good friend. 7.Synthesis of aminoester 1 1 , as reported in reference 2, has been slightly modified: (a) allyltrimethylsilane. BF, .Et , O ; qUant.(b) i ozonolysis, ii Winig reaction, iii deprotection ; 60%.