Water Control over the Chemoselectivity of a Ti/Ni Multimetallic System: Heck- or Reductive-Type Cyclization Reactions of Alkyl Iodides
摘要:
A versatile Ti/Ni multimetallic protocol is described for the efficient catalysis of two different reactions, namely a Heck- and reductive-type cyclization of alkyl iodides, in the absence or presence of water, respectively. Noteworthy, the versatility of Ti(III) chemistry allows an oxidative ending step under reductive conditions to give Heck-type products, and the good H-atom transfer capabilities of Ti(III)-aqua complexes ensure reductive-type cyclizations.
A reductive dicarbofunctionalization reaction of alkenes has been developed and applied to the preparation of substituted carbo- and heterocycles. The reaction conditions avoid the use of air-sensitive organometallic reagents, and are compatible with a broad range of bromo-electrophiles and a wide variety of substituents to give cyclic products in excellent yields.