Stereospecific Synthesis of Tetrahydronaphtho[2,3‑b]furans Enabled by a Nickel-Promoted Tandem Reductive Cyclization

A Ni-mediated cascade to a stereoselective synthesis of trans-tetrahydronaphtho­[2,3-b]­furans is efficiently achieved for the first time. The mild reductive system can be easily generated from inexpensive and air-stable materials and shows a broad positional tolerance of substituents that were previously difficult or impossible to access by other methods. Facile syntheses toward new analogues of therapeutic agents (iso)­deoxypodophyllotoxin are also reported. In addition, the inherent substrate control is disclosed for the observed unique stereoselectivities during cyclizations.