333339-61-0Relevant academic research and scientific papers
Efficient preparation of optically active (S)-(-)-3-methyl-γ-butyrolactone by catalytic asymmetric hydrogenation using chiral N-substituted pyrrolidinebisphosphine rhodium complexes
Takeda,Tachinami,Hosokawa,Aburatani,Inoguchi,Achiwa
, p. 2706 - 2708 (1991)
(S)-(-)-2-Methyl succinamic acid, which is a good precursor of (S)-(-)-3-methyl-γ-butyrolactone, can be prepared by homogeneous asymmetric hydrogenation of 2-methylene succinamic acid catalyzed by (2S,4S)-N-substituted-4-(diphenylphosphino)-2-[(diphenylphosphino)-meth yl]pyrrolidine-rhodium complexes. Various N-substituted pyrrolidine-bisphosphines were synthesized to find the optimum ligand for this purpose and to compare the effects of the N-substituents.
Highly efficient asymmetric hydrogenation of 2-methylenesuccinamic acid using a Rh-DuPHOS catalyst
Cobley, Christopher J.,Lennon, Ian C.,Praquin, Celine,Zanotti-Gerosa, Antonio,Appell, Robert B.,Goralski, Christian T.,Sutterer, Angela C.
, p. 407 - 411 (2003)
An extremely efficient route to highly enantiomerically enriched 2-methylsuccinamic acid via asymmetric hydrogenation has been developed. By using [(S,S)-Et-DuPHOS Rh COD]BF4 as the precatalyst under a set of broadly optimised process parameters, (R)-2-methylsuccinamic acid was obtained in 96% ee at a substrate-to-catalyst ratio (S/C) of 100000 (average turnover frequency ～13000 h-1). The exclusion of chloride-containing contaminants in the substrate was found to be crucial in obtaining exceptionally low catalyst loadings. This material could be upgraded with a single-crystal digestion to yield (R)-2.methylsuccinamic acid in >99.5% ee containing less than 1 ppm rhodium.
DiPAMP's big brother "i-Pr-SMS-Phos" exhibits exceptional features enhancing rhodium(I)-catalyzed hydrogenation of olefins
Stephan, Michel,Sterk, Damjan,Mohar, Barbara
supporting information; scheme or table, p. 2779 - 2786 (2010/03/25)
Switching Knowles DiPAMP's {DiPAMP = l,2-bis[(o-anisyl)(phenyl)phosphino] ethane} MeO groups with i-PrO ones led to the iPr-SMS-Phos {i-Pr-SMS-Phos = l,2-bis[(o-isopropoxyphenyl)(phenyl)phosphino]ethane} ligand which displayed a boosted catalyst activity coupled with an enhanced enantioselectivity in the rhodium(I)catalyzed hydrogenation of a wide-range of representative olefinic substrates (dehydro-a-amido acids, itaconates, acrylates, enamides, enol acetates, α,α-diarylethylenes, etc). The rhodium(I)-(i-PrSMS-Phos) catalytic profile was investigated revealing its structural attributes and robustness, and in contrast to the usual trend, 31P NMR analysis revealed that its methyl (Z)-α-acetamidocinnamate (MAC) adduct consisted of a reversed diastereomeric ratio of 1.4:1 in favour of the most reactive diastereomer.
