30646-01-6Relevant academic research and scientific papers
New hydrogen-bonding organocatalysts: Chiral cyclophosphazanes and phosphorus amides as catalysts for asymmetric Michael additions
Klare, Helge,Neudoerfl, Joerg M.,Goldfuss, Bernd
supporting information, p. 224 - 236 (2014/02/14)
Ten novel hydrogen-bonding catalysts based on open-chain PV-amides of BINOL and chinchona alkaloids as well as three catalysts based on rigid cis-PV-cyclodiphosphazane amides of N1,N1-dimethylcyclohexane-1,2-diamine have been developed. Employed in the asymmetric Michael addition of 2-hydroxynaphthoquinone to β-nitrostyrene, the open-chain 9-epi-aminochinchona-based phosphorus amides show a high catalytic activity with almost quantitative yields of up to 98% and enantiomeric excesses of up to 51%. The cyclodiphosphazane catalysts show the same high activity and give improved enantiomeric excesses of up to 75%, thus representing the first successful application of a cyclodiphosphazane in enantioselective organocatalysis. DFT computations reveal high hydrogen-bonding strengths of cyclodiphosphazane PV-amides compared to urea-based catalysts. Experimental results and computations on the enantiodetermining step with cis-cyclodiphosphazane 14a suggest a strong bidentate H-bond activation of the nitrostyrene substrate by the catalyst.
Kinetics of Hydrolysis of N,N'-Di-p-methoxyphenyl-phosphorodiamidic Chloride
Sahni, V.,Prabha, S.
, p. 485 - 489 (2007/10/02)
Hydrolysis of N-(p-methoxyphenyl)phosphorodiamidic chloride has been studied in the acid region, 0.01 to 8.0 M HCl at 40 deg C (acetic acid-water 20percent (v/v).Ionic strength effect differentiates two contributory forms, the neutral as well as the conju
