C1-Benzyl and benzoyl isoquinoline synthesis through direct oxidative cross-dehydrogenative coupling with methyl arenes

Abstract

An oxidative cross-dehydrogenative coupling (CDC) of isoquinolines with methyl arenes has been developed, allowing for the facile synthesis of a broad range of structurally diverse C₁-benzyl and -benzoyl isoquinolines. The direct use of readily available methyl arenes as coupling partners avoids unproductive steps for preactivating the functional group installation, and is therefore attractive. The method exhibits excellent chemoselectivity, affording exclusive benzylated products in the presence of DTBP and a catalytic amount of Y(OTf)₃, and yielding benzoylated ones with TBHP and a catalytic amount of MnO₂.