New synthetic route to homooxacalix[n]arenes via reductive coupling of diformylphenols

Reductive homocoupling of 4-substituted-2,6-diformylphenols with Et3SiH in the presence of Me3SiOTf gave homooxacalix[n]arenes (1n·R, n=3, 4) in moderate yields. Heterocoupling reaction of 4-substituted-2,6-diformylphenols with tris(trimethylsilyl) ether of 4-substituted-2,6-bis(hydroxymethyl)phenols afforded homooxacalix[n]arenes (23·R1·R2·Rm and 24·R1·R2·R1·Rm, m=1, 2) with different substituents in a one-pot fashion.