Recent progress in the reduction of benzene derivatives and their industrial applications

Cyclohexane (CHA), cyclohexene (CHE), and 1,4-cyclohexadiene (CHD) derivatives have a wide variety of applications and scope in synthetic and industrial organic chemistry. These cyclic hydrocarbons are found in a variety of natural products, including herbal plants and fruits as basic fragrance components. The extraction and isolation of these essential hydrocarbons are too complex and difficult to pursue. However, the reduction of benzene and its derivatives is an essential and effective approach for producing CHA, CHE, and CHD derivatives. To obtain CHA, CHE, and CHD derivatives, several types of reduction techniques for benzene and its derivatives have been developed over the years, including various forms of catalytic hydrogenation, Benkeser reduction, classic and many modified Birch reductions such as ammonia-free, metal-free photochemical, solvent-free, electrochemical and electride-mediated Birch reduction. In this study, the comparison of chemoselectivity, regioselectivity, reaction conditions, reduction efficiency, and environmentally acceptable approaches of these techniques used for benzene reduction are summarized. Graphical abstract