A Convenient Method for the Synthesis of Protic 2-(Tertiary phosphino)-1-amines and Their Cp*RuCl Complexes

Abstract

A Variety of protic 2-(tertiary phosphino)-1-amines (R 2 PCH 2 CHR′NHR′′, P-NH) haVe been prepared from 2-oxazolidinones and secondary phosphines using a newly deVeloped acid-promoted decarboxylatiVe C-P bond formation reaction. Treatment of the resulting chiral P-NH compounds with Cp*RuCl(isoprene) in CH 2 Cl 2 smoothly furnished chiral Cp*RuCl(P-NH) complexes with a typical three-legged pianostool structure, which proVe to be excellent catalyst precursors for asymmetric reactions, including the isomerization of allylic alcohols and hydrogenation of imides.

Chiral multifunctional thiourea-phosphine catalyzed asymmetric [3 + 2] annulation of Morita–Baylis–Hillman carbonates with maleimides

“…Hence, we initially used multifunctional thiourea-phosphine (TP), which could be easily prepared from L-phenylalanine in four steps [57], as a catalyst to investigate the asymmetric [3 + 2] annulation of N -phenylmaleimide ( 1a ) with MBH carbonate 2a in toluene at room temperature. We were pleased to find that the corresponding highly functionalized cyclopentene 3a was obtained in 54% yield with 96% ee after 24 h (Table 1, entry 1).…”

Synthesis, structural characterization, and reactivity of Cp*Ru(N-phosphinoamidinate) complexes

“…1), 1,[9][10][11][12] reports documenting the preparation of isolable, coordinatively unsaturated, and formally 16-electron Cp*Ru( 2 -LϳX) chelate complexes supported by monoanionic, LX-type ligands are rare and involve primarily synthetic investigations of 2 -N,N amidinate (B) 1,2,13 or ␤-diketiminate (C) 14,15 complexes. It is worthy of mention that analogous Cp*Ru( 2 -PϳN) species, 16 derived from 2-(diphenylphosphino)ethylamine and related ligands (D), have been implicated by Ikariya and co-workers as key intermediates in a diversity of synthetically useful metal-catalyzed transformations including the chemoselective hydrogenolysis of epoxides, 17 the isomerization of allylic alcohols, 18 the oxidative lactonization of 1,4-diols, 19 and the hydrogenation of imides. 20,21 Control experiments featured in these reports confirm the importance of tethered phosphino and primary/secondary amine moieties as a means of achieving optimal catalytic performance via Ru/NH bifunctional catalysis.…”

Bifunctional transition metal‐based molecular catalysts for asymmetric CC and CN bond formation

“…Hence, further extension of the number of available catalysts of this kind might result in the discovery of new effective asymmetric catalytic reactions. For example, changing the amine ligands in the arene–Ru complexes 1 from N ‐sulfonylated diamines to N,N ‐dimethylaminoethylamines and 2‐phosphinoethylamines in the Cp*Ru complexes leads to a significant change in catalytic performance 23. There is little doubt that further modifications of the catalyst structures coupled with a deeper understanding of the mechanisms of enantioselection will lead to further breakthroughs in rational catalyst design and effective enantioselective transformations.…”