One stone three birds: Ni-catalyzed asymmetric allenylic substitution of allenic ethers, hydroalkylation of 1,3-enynes and double alkylation of enynyl ethers

Abstract

The development of low-cost, earth-abundant and environmentally benign transition metal catalysts, which can catalyze multiple different types of asymmetric reactions, is an important objective in modern asymmetric catalysis. Herein we demonstrate that a chiral Ni/P-Phos catalyst achieves three types of asymmetric reactions: allenylic substitution of racemic allenic ethers, 1,4-hydroalkylation of prochiral 1,3-enynes and double alkylation of newly designed enynyl ether reagents. Three methods complement each other and produce various axially chiral allene derivatives bearing a pyrazolidine-3,5‑dione unit, which is widely present in drugs and biologically active molecules with versatile pharmacological activities.