Recent Progress in the Synthesis of Heterocycles through Base Metal-Catalyzed Acceptorless Dehydrogenative and Borrowing Hydrogen Approach

Development in the area of acceptorless dehydrogenation (AD) and borrowing hydrogen (BH) catalysis emerge as one of the potential tools for various C-C and C-heteroatom bond forming reactions. Alcohols, which are important lignocellulosic biomass products, act as pivotal electrophilic coupling partners in such processes and interestingly only H-2 or H2O is eliminated as a byproduct. Initially, the area was developed by the use of noble metal catalysts. Recently, base metals such as Mn, Fe, Co, and Ni proved to be environmentally benign and inexpensive alternatives for the noble metals in the application of AD and BH methods. This transition metal catalyzed AD and BH approaches also allow access toward a plethora of structurally important heterocyclic molecules via environmentally benign and atom economical strategy. Herein, we summarize the current and rising expansion of base metal catalyzed heterocycles synthesis through acceptorless dehydrogenation and borrowing hydrogenation strategy.