title: Iminium salts of omega-dithiafulvenylpolyenals: an easy entry to the corresponding aldehydes and doubly proaromatic nonlinear optic-phores.
abstract: 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.
authors.affiliation: Departamento de Química Orgánica, ICMA, Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Alías
authors.forename: Raquel
authors.initials: R
authors.lastname: Andreu
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Blesa
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Cerdán
authors.forename: Santiago
authors.initials: S
authors.lastname: Franco
authors.forename: Javier
authors.initials: J
authors.lastname: Garín
authors.forename: Carolina
authors.initials: C
authors.lastname: López
authors.forename: Jesús
authors.initials: J
authors.lastname: Orduna
authors.forename: Jorge
authors.initials: J
authors.lastname: Sanz
authors.forename: Raquel
authors.initials: R
authors.lastname: Alicante
authors.forename: Belén
authors.initials: B
authors.lastname: Villacampa
authors.forename: Magali
authors.initials: M
authors.lastname: Allain