Cu(I)-catalyzed cross dehydrogenative coupling (CDC) of ethers and substituted styrenes

Abstract

The development of mild and selective methods for a cross dehydrogenative coupling (CDC), using commercial low-cost unactivated alkenes with tetrahydrofuran derivatives as the source of ether and solvent, remains a challenge. We present in this work a Cu(I)-mediated CDC with tetrahydrofuran derivatives (THF) and unactivated alkenes via a dehydrogenative coupling of C(sp [3])−H and C(sp [2])−H bonds, yielding α-functionalized cyclic ethers. The reaction exhibited excellent E/Z selectivity and good to excellent yields (51%–88%). We also hypothesized for a β-H elimination route which confirmed the radical pathway of intermediate (E) for ether alkenylation/functionalization. This methodology can be employed for a broad variety of aromatic alkenes, hetero aromatic alkenes and cyclic ethers providing valuable insights for the design of versatile alkenyl cyclic ethers.