Recently, we have demonstrated ene-hydrazides prepared from enol triflates in regiochemically defined form may undergo Fischer indolization reactions with no regiochemical scrambling. This conceptually new synthetic strategy has been successfully applied to the total syntheses of (+)-aspidospermidine and (-)-tabersonine.
Toward further development of our new strategy, we have envisaged a new synthetic route to (-)-alloaristoteline, a highly strained aristotelia alkaloid. In this new program, we envisioned enol triflate 1 could be prepared from the corresponding enone by a Michael addition of a Gilman reagent followed by an in-situ triflation. Subsequent C-N coupling with phenyl hydrazide would afford the key intermediate ene-hydrazide 2. Regioselective Fischer indolization would furnish indole 3, the main skeleton of (-)-alloaristoteline. Presented herein would be our progress toward the synthesis of (-)-alloaristoteline.
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