[摘要]：A short, high-yielding route to w-dithiafulvenylpolyenals I (X = O; n = 2, 3) via the corresponding iminium salts I (X = NMe2) and starting from trimethyl-1,3-dithiolium tetrafluoroborate is reported. The Knoevenagel reactions of either I (X = O; n = 1, 2) or I (X = NMe2; n = 1 - 3) with isoxazolone-contg. acceptors afford merocyanines II and III, in a process that is often accompanied by a vinylene-shortening side reaction. Exptl. and theor. studies reveal that compds. II and III, featuring two proarom. end groups, are strongly polarized and show good second-order nonlinear optical responses.
