Regioselective and Chemoselective Reduction of Naphthols Using Hydrosilane in Methanol: Synthesis of the 5,6,7,8-Tetrahydronaphthol Core.

A regioselective and chemoselective method for catalytic synthesis of biologically interesting 5,6,7,8-tetrahydronaphthols by reduction of naphthols was described. The side aromatic hydrocarbons in naphthols were site-selectively reduced, using hydrosilanes in methanol, allowing for retaining functional phenol scaffolds intact. It presents a rare example of using low-cost and air-stable hydrosilane for catalytic reduction of unactivated aromatic hydrocarbons under mild conditions. This reaction is scalable and proceeds in high selectivity without the formation of 1,2,3,4-tetrahydronaphthol byproducts with toleration of sensitive functionalities such as bromide, chloride, fluoride, ketone, ester, and amide.