Pd-Catalyzed Regioselective Iminothiolation of Alkynes: A Remarkable Effect of the CF₃ Group of Iminosulfides

Abstract

Pd-catalyzed iminothiolation of alkynes took place to afford 4-SR substituted 1-azadienes regioselectively.

Trifluoroacetimidoyl halides: a potent synthetic origin

“…Kuniyasu, Kambe and co-workers demonstrated a Pd-catalyzed iminothiolation of alkynes by using trifluoromethylated iminosulfides to construct 4-sulfur-functionalized 1-azadienes (Scheme 32). 52 The iminosulfides could be readily prepared by the base-mediated coupling of trifluoroacetimidoyl chlorides with thiols. In the iminothiolation reaction, the existence of the CF 3 group was very essential for the successful transformation and the milder conditions enabled the addition of terminal alkynes compared with the internal alkynes.…”

C–S Bond Activation

“…The insertion products, 3-butenoyl thioesters, were isomerized to acrylic thioesters under the conditions. Thiocarbonates [132], thiocarbamates [133], and imidoyl sulfides [134] as well as thioesters reacted with alkynes (Scheme 60). In these cases, decarbonylation did not take place probably due to the presence of heteroatom groups.…”

Transition-metal mediated carbon–sulfur bond activation and transformations

“…161 The stoichiometric reactions of 204 and Pt(PPh 3 ) 4 were performed in C 6 D 6 at 25 1C and monitored by 31 81)). 164 The introduction of a CF 3 group into the iminocarbon moiety of iminosulfide substrates (205) is key to achieving the reaction. The oxidative addition of 205 to the Pd(0) species triggered the reaction to form a C-S cleavage complex by Pd metal.…”