Intramolecular Hydroamination with Homogeneous Zinc Catalysts: Evaluation of Substituent Effects in N,N′‐Disubstituted Aminotroponiminate Zinc Complexes

Abstract

A series of symmetrical and unsymmetrical N,N'-disubstituted aminotroponimines (ATIHs) have been prepared. Substituents ranging from linear to cyclic alkyl groups, chelating ethers, and aryl groups were employed. The corresponding aminotroponiminate zinc complexes were then synthesized and characterized by a number of techniques, including by X-ray crystallography. Herein we report on the investigations into their activity in the intramolecular hydroamination of nonactivated alkenes. We also demonstrate that complexes bearing ligands with cyclic alkyl groups show superior activity in a number of selected reactions with functionalized aminoalkenes.

Heterofunctionalization catalysis with organometallic complexes of calcium, strontium and barium

“…Not only were reactions of 2,2-disubstituted 1-amino-5-hexene substrates accompanied by alkene isomerization products, but also the cyclization of 1-amino-2,2-diphenyl-6-heptene could not be achieved with this catalyst. Nevertheless, both 1 and 2 demonstrated activities commensurate with those reported for the organo(III)lanthanides (Hong & Marks 2004) and in vast excess of those reported for organozinc complexes (Dochnahl et al , 2007Meyer et al 2006).…”

{CH2(PPh2=NSiMe3)(PPh2=S)} and {CH(PPh2=NSiMe3)(Ph2P=S)}– as Ligands in Zinc Chemistry: Synthesis and Structures

“…Because various aminotroponiminate zinc alkyl and amido complexes have been used successfully in hydroamination/cyclization reactions, [8][9][10][11][12]16,18] we performed catalytic studies by using compound 4 as catalyst and [PhNMe 2 H][B(C 6 F 5 ) 4 ] as co-catalyst in the hydroamination/ cyclization reaction. Three different amino-olefins and one aminoalkyne were used as substrates.…”

“…We have recently developed, among others, various aminotroponiminate zinc alkyl and amido complexes as catalysts for the hydroamination reaction. [8][9][10][11][12][13][14][15][16][17][18] We have also reported on bis(phosphinimino)-methanide zinc complexes. [40,41] Bis(phosphinimino)methane {CH 2 3 )(PPh 2 =S)CH}ZnPh], respectively.…”

Aminotroponiminate zinc complexes as catalysts for the intramolecular hydroamination

“…5 [122,139,140]. Besides cyclic and non cyclic aliphatic and aromatic groups with different steric demand, ether substituents were introduced (Fig.…”

“…Regarding aminotroponiminate ligands ( Fig. 4) [138], the steric effects can be controlled by modification of the N-substituents, while the electronic properties are basically influenced by altering the ring substituents [139].…”