- Bifunctional iminophosphorane organocatalysts for enantioselective synthesis: Application to the ketimine nitro-Mannich reaction
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The design, synthesis, and development of a new class of modular, strongly basic, and tunable bifunctional Bronsted base/H-bond-donor organocatalysts are reported. These catalysts incorporate a triaryliminophosphorane as the Bronsted basic moiety and are readily synthesized via a last step Staudinger reaction of a chiral organoazide and a triarylphosphine. Their application to the first general enantioselective organocatalytic nitro-Mannich reaction of nitromethane to unactivated ketone-derived imines allows the enantioselective construction of β-nitroamines possessing a fully substituted carbon atom. The reaction is amenable to multigram scale-up, and the products are useful for the synthesis of enantiopure 1,2-diamine and α-amino acid derivatives.
- Nunez, Marta G.,Farley, Alistair J. M.,Dixon, Darren J.
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supporting information
p. 16348 - 16351
(2013/12/04)
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- Enantioselective Strecker-type reaction of phosphinoyl ketimines catalyzed by a chiral Zr-bipyridyldiol catalyst
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An enantioselective Strecker reaction of N-diphenylphosphinoyl ketimines with TMSCN employing a chiral zirconium complex formed from chiral bipyridyl diol 1 as catalyst is described. The catalytic efficiency of chiral ligand 1 with other Lewis acids was also explored. Higher yields (50-85%) with moderate to good enantioselectivities (30-80%) were achieved for a variety of N-diphenylphosphinoyl ketimines.
- Chen, Yi-Jing,Chen, Chinpiao
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experimental part
p. 2201 - 2209
(2009/04/05)
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