Iminium salts of omega-dithiafulvenylpolyenals: an easy entry to the corresponding aldehydes and doubly proaromatic nonlinear optic-phores.
A short, high-yielding route to omega-dithiafulvenylpolyenals (1) via the corresponding iminium salts (2) and starting from trimethyl-1,3-dithiolium tetrafluoroborate is reported. The Knoevenagel reactions of either 1 or 2 with isoxazolone-containing acceptors afford merocyanines 7 and 9, in a process that is often accompanied by a vinylene-shortening side reaction. Experimental and theoretical studies reveal that compounds 7 and 9, featuring two proaromatic end groups, are strongly polarized and show good second-order nonlinear optical responses.
Alías
Silvia
S
Departamento de Química Orgánica, ICMA, Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain.
Andreu
Raquel
R
Blesa
María Jesús
MJ
Cerdán
Miguel Angel
MA
Franco
Santiago
S
Garín
Javier
J
López
Carolina
C
Orduna
Jesús
J
Sanz
Jorge
J
Alicante
Raquel
R
Villacampa
Belén
B
Allain
Magali
M