Efficient Enantioselective Total Synthesis of (-)-Horsfiline

A new efficient and concise enantioselective synthetic method for (-)-horsfiline is reported. (-)-Horsfiline could be obtained from diphenylmethyl tert-butyl malonate in 9 steps (32%,>99%ee) by using the enantioselective phase-transfer catalytic allylation (91%ee) as the key step. This approach can be applied as a practical route for the large-scale synthesis of spirooxindole natural products, which enables a systematic investigation of their biological activity to be performed.