Novel dual Lewis acid-Lewis base binders as potential hydrogen and carbonyl activators

Abstract

A series of new “frustrated Lewis pairs” (FLPs), including chiral versions, with a predefined spatial relationship between the basic and acidic centers is proposed. Several synthetic protocols toward the targets were investigated: through an aryllithium – haloborane coupling; using organotin reagents and a chiral diazaborolidine; and through organoboranes RBH2 as the boron component. Further development of the project is discussed in light of the discovered data.

The intermolecular system consisting of 8-bromo-2-methylquinoline and (C₆F₅)₃B was shown to exist in the form of an FLP. This FLP is not capable of heterolytic H-H bond cleavage with formation of an isolable adduct either at 1 atm or at 4 atm of H₂.