Aminotroponate/Aminotroponiminate Zinc Complexes Functionalized Mesoporous Silica Catalysts for Intramolecular Hydroamination of Non-Activated Alkenes with Varied Steric and Electronic Properties

Earth-Abundant 3d Transition Metal Catalysts for Hydroalkoxylation and Hydroamination of Unactivated Alkenes

This review summarizes the most noteworthy achievements in the field of C–O and C–N bond formation by hydroalkoxylation and hydroamination reactions on unactivated alkenes (including 1,2- and 1,3-dienes) promoted by earth-abundant 3d transition metal catalysts based on manganese, iron, cobalt, nickel, copper and zinc. The relevant literature from 2012 until early 2021 has been covered.

Origin of stereoselectivity in an isothiourea catalyzed Michael addition reaction of aryl ester with vinyl disulfone

The origin of stereoselectivity in an isothiourea-catalyzed addition reaction of aryl ester with vinyl disulfone was explored for the first time.

On the understanding of BF3·Et2O-promoted intra- and intermolecular amination and oxygenation of unfunctionalized olefins

BF₃·Et₂O was found to be effective for the amination and oxygenation of unfunctionalized olefins. In the presence of 3 equiv. of BF₃·Et₂O, intra- and intermolecular amination and oxygenation reactions could be realized in up to 99% isolated yields.

Phenalenyl-based organozinc catalysts for intramolecular hydroamination reactions: a combined catalytic, kinetic, and mechanistic investigation of the catalytic cycle

Herein, we report the synthesis and characterization of two organozinc complexes that contain symmetrical phenalenyl (PLY)-based N,N-ligands. The reactions of phenalenyl-based ligands with ZnMe(2) led to the formation of organozinc complexes [N(Me),N(Me)-PLY]ZnMe (1) and [N(iPr),N(iPr)-PLY]ZnMe (2) under the evolution of methane. Both complexes (1 and 2) were characterized by NMR spectroscopy and elemental analysis. The solid-state structures of complexes 1 and 2 were determined by single-crystal X-ray crystallography. Complexes 1 and 2 were used as catalysts for the intramolecular hydroamination of unactivated primary and secondary aminoalkenes. A combined approach of NMR spectroscopy and DFT calculations was utilized to obtain better insight into the mechanistic features of the zinc-catalyzed hydroamination reactions. The progress of the catalysis for primary and secondary aminoalkene substrates with catalyst 2 was investigated by detailed kinetic studies, including kinetic isotope effect measurements. These results suggested pseudo-first-order kinetics for both primary and secondary aminoalkene activation processes. Eyring and Arrhenius analyses for the cyclization of a model secondary aminoalkene substrate afforded ΔH(≠) =11.3 kcal mol(-1) , ΔS(≠) =-35.75 cal K(-1)  mol(-1) , and E(a) =11.68 kcal mol(-1) . Complex 2 exhibited much-higher catalytic activity than complex 1 under identical reaction conditions. The in situ NMR experiments supported the formation of a catalytically active zinc cation and the DFT calculations showed that more active catalyst 2 generated a more stable cation. The stability of the catalytically active zinc cation was further supported by an in situ recycling procedure, thereby confirming the retention of catalytic activity of compound 2 for successive catalytic cycles. The DFT calculations showed that the preferred pathway for the zinc-catalyzed hydroamination reactions is alkene activation rather than the alternative amine-activation pathway. A detailed investigation with DFT methods emphasized that the remarkably higher catalytic efficiency of catalyst 2 originated from its superior stability and the facile formation of its cation compared to that derived from catalyst 1.