A Fast Procedure for the Reduction of Azides and Nitro Compounds Based on the Reducing Ability of Sn(SR)3- Species
Martí Bartra, Pedro Romea, Fèlix Urpí, and Jaume Vilarrasa
Tetrahedron 46(2), 587-594 (1990) (https://www.thevespiary.org/rhodium/Rhodium/pdf/nitro-azide.red.tin-thiolate.pdf)
(https://www.thevespiary.org/rhodium/Rhodium/pdf/nitro-azide.red.tin-thiolate.pdf)
Abstract
Tin(II) complexes prepared by treatment of SnCl2 or Sn(SR)2 with appropriate amounts of RSH and Et3N appear to be the best reducing agents for azides (to amines) reported so far. These tin(II) complexes also reduce primary and secondary aliphatic nitro compounds to oximes, usually within minutes at r.t. or hours in the cold, and tertiary aliphatic as well as aromatic nitro compounds to afford the corresponding hydroxylamines. In general, azides react more rapidly than nitro substituents, whereas carbonyl groups, sulphoxides, sulphones, nitriles, and esters are practically unreactive under the same conditions. Some mechanistic details of the reaction of Sn(SPh)3- with azides and nitro compounds have also been elucidated.