SmI2-induced reductive cyclization of (E)- and (Z)-β-alkoxyvinyl sulfones with aldehyde

SmI 2 -induced reductive cyclization of ( E )- and ( Z )-β-alkoxyvinyl sulfones with aldehyde stereoselectively afforded 2,6- syn -2,3- trans - and 2,6- syn -2,3- cis -tetrahydropyrans, respectively. The product having a sulfonylmethyl group was converted to a cyclic ether having a methyl group by reduction with Raney-Ni.