(Z)-3-p-tolylsulfinylacrylonitriles as chiral dipolarophiles: reactions with diazoalkanes

J L Ruano; S A de Diego; D Blanco; A M Castro; M R Martín; J H Ramos

doi:10.1021/ol016481o

(Z)-3-p-tolylsulfinylacrylonitriles as chiral dipolarophiles: reactions with diazoalkanes

Org Lett. 2001 Oct 4;3(20):3173-6. doi: 10.1021/ol016481o.

Authors

J L Ruano¹, S A de Diego, D Blanco, A M Castro, M R Martín, J H Ramos

Affiliation

¹ Departamento de Química Orgánica, Universidad Autónoma de Madrid, Cantoblanco, 28049-Madrid, Spain. joseluis.garcia.ruano@uam.es

PMID: 11574023
DOI: 10.1021/ol016481o

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.