ortho-Alkynyl Benzyl Alcohols as C6 Synthons in Regioselective Construction of Polysubstituted Naphthalenes.

A straightforward methodology for the assembly of polysubstituted naphthalenes from ortho-alkynyl benzyl alcohols, enabled by using catalytic amounts of Tf2O, has been developed. This transformation not only features transition-metal free and without using other bases and additives but also provides a new synthetic application for ortho-alkynyl benzyl alcohols, i.e., as C6 synthons for the construction of PAHs.

Assembly of 5H-dibenzo[a,d]cycloheptenes by a formal [5 + 2] annulation of ortho-aryl alkynyl benzyl alcohols with arenes.

A new synthetic methodology for the synthesis of 5H-dibenzo[a,d]cycloheptenes from ortho-aryl alkynyl benzyl alcohols and arenes via a Tf2O-mediated formal [5 + 2] annulation reaction has been achieved. From this transformation, structurally diverse 5H-dibenzo[a,d]cycloheptenes were achieved in moderate to good yields. This transformation probably involves an intermolecular Friedel-Crafts-type alkylation and a subsequent intramolecular 7-endo-dig cyclization in one pot, highlighting the high efficiency, regioselectivity, and step-economy of this protocol.