title: (Z)-3-p-tolylsulfinylacrylonitriles as chiral dipolarophiles: reactions with diazoalkanes.
abstract: [reaction: see text] The dipolarophilic reactivity of enantiopure (Z)-3-p-tolylsulfinylacrylonitriles (1) has been evaluated with diazoalkanes. 3-Cyanopyrazoles are obtained when R = H, but with R = alkyl (Bn, n-Bu, and t-Bu) only one cycloadduct (4 or 5) is formed in high yield under mild conditions, therefore evidencing a complete control of the regioselectivity and the endo/exo and pi-facial selectivities. These reactions are a new straightforward entry to the synthesis of pyrazolines and related structures and reveal the excellent dipolarophilic features of (Z)-sulfinylacrylonitriles.
authors.affiliation: Departamento de Química Orgánica, Universidad Autónoma de Madrid, Cantoblanco, 28049-Madrid, Spain. joseluis.garcia.ruano@uam.es
authors.forename: J L
authors.initials: JL
authors.lastname: Ruano
authors.forename: S A
authors.initials: SA
authors.lastname: de Diego
authors.forename: D
authors.initials: D
authors.lastname: Blanco
authors.forename: A M
authors.initials: AM
authors.lastname: Castro
authors.forename: M R
authors.initials: MR
authors.lastname: Martín
authors.forename: J H
authors.initials: JH
authors.lastname: Ramos