Two-step synthesis of D3 and C3h cryptophanes
Abstract
Dihalides X–(Z)–X, [Z =(CH2)n; n= 1–7 or CH2CHCHCH2] react with the phenol group of vanillyl alcohol to give the dialkylated derivatives HOCH2–Ar–O–(Z)–O–Ar–CH2OH (2), which in turn, in the presence of formic acid, afford the corresponding D3 cryptophanes (3), with, in some cases, minor amounts of the C3h isomers (4).