InBr3 as a versatile and highly efficient catalyst for the synthesis of 3-allyl- and 3-benzylindoles

Indoles undergo smooth alkylation with allylic and benzylic alcohols in the presence of 10 mol % of InBr₃ under mild conditions to produce 3-allyl- and 3-benzyl indoles, respectively, in excellent yields and with high selectivity. This is the first example of the alkylation of indoles with benzylic alcohols using InBr₃ as an acid catalyst.