Synthesis of 4,4'-Disubstituted and Spiro-tetrahydroquinolines via Photochemical Cyclization of Acrylanilides and the First Synthesis of (.+-.)-trans-Vabicaserin

The synthesis of vabicaserin analogues bearing a quaternary center or spiro substitution at the 4-position has been studied via a [6π]-acrylanilide cyclization employing flow photochemistry in a mesoscale and microfluidic flow photoreactor. The method is also used to synthesize 4,4′-disubstituted tetrahydroquinolines and, furthermore, enables the first synthesis of (±)- trans -vabicaserin.