title: Formation of a Cationic Vinylimido Group upon C-H Activation of Nitriles by Trialkylamines in the Presence of TaCl5.
abstract: We report a new CH3CN activation mode where an imido group is directly formed by deprotonation of the nitrile coordinated to the highly Lewis acidic Ta(V) center. The unexpected deprotonation of TaCl5(CH3CN) by NEt3 resulted in isolation of the triethylammonium vinylimido complex [HNEt3][Ta(NC(CH2)NEt3)Cl5]. The reaction is proposed to proceed through rearrangement of the initial nucleophilic carbanion to the electrophilic azaallene/carbocation intermediate. The use of more sterically hindered (i-Pr)CN and weakly nucleophilic N(i-Pr)2Et resulted in the isolation of a vinylimido group formed upon dimerization of deprotonated nitriles, suggesting deprotonation as the first step of the transformation.
authors.affiliation: Department of Chemistry and Biochemistry, University of South Carolina , 631 Sumter Street, Columbia, South Carolina 29208, United States.
authors.forename: Md Mamdudur
authors.initials: MM
authors.lastname: Rahman
authors.affiliation: Department of Chemistry and Biochemistry, University of South Carolina , 631 Sumter Street, Columbia, South Carolina 29208, United States.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Smith
authors.affiliation: Department of Chemistry and Biochemistry, University of South Carolina , 631 Sumter Street, Columbia, South Carolina 29208, United States.
authors.forename: Dmitry V
authors.initials: DV
authors.lastname: Peryshkov