1159633-62-1Relevant academic research and scientific papers
Transfer hydrogenations of alkenes with formate on Pd/C: Synthesis of dihydrocinchona alkaloids
Wu, Haotian,Hintermann, Lukas
, p. 888 - 892 (2013/05/09)
Protocols for preparative (1-80 gram scale) transfer hydrogenations of alkenes over a palladium on carbon catalyst using formic acid/ammonium formate as hydrogen donor are presented. Cinchona alkaloids have been converted to their dihydro derivatives in >94% yield. Georg Thieme Verlag Stuttgart - New York.
Organocatalytic stereoisomerization versus alkene isomerization: Catalytic asymmetric synthesis of 1-hydroxy-trans -2,5-diphenylphospholane 1-oxide
Hintermann, Lukas,Schmitz, Marco,Maltsev, Olegv.,Naumov, Pance
supporting information, p. 308 - 325 (2013/03/14)
The potential for an organocatalytic asymmetric stereoisomerization or alkene isomerization as atom-economic reaction with minimal structural change was investigated. The McCormack cycloaddition of 1,4-diarylbuta-1,3-dienes with (dialkylamino)dichlorophosphane and aluminum trichloride gives meso-2,5-diaryl-1-(dialkylamino)-1-oxo-2,5-dihydro-1H-phospholes, which were identified as suitable substrates for asymmetric isomerization to (1R,5R)-2,5-diaryl-1-(dialkylamino)-1-oxo-4,5-dihydro-1H-phospholes in the presence of bifunctional organocatalysts (cinchona alkaloids, Takemoto catalyst) in up to 91% ee and quantitative yield. The substrate range and the mechanism of the catalysis were studied. The reaction involves proton abstraction by the base, but a primary deuterium KIE is absent. Enriched (1R,5R)-1-(diethylamino)- 1-oxo-2,5-diphenyl-4,5-dihydro-1H-phosphole was hydrolyzed to (5R)-1-hydroxy-1-oxo-2,5-diphenyl-4,5-dihydro-1H-phosphole, which was hydrogenated diastereoselectively under dissolving metal conditions to give (2R,5R)-1-hydroxy-1-oxo-2,5-diphenylphospholane (Fiaud's acid) in preference to meso-1-hydroxy-1-oxo-2,5-diphenylphospholane. An asymmetric catalytic total synthesis of Fiaud's acid, which is a building block for chiral phospholane synthesis, has been realized in five steps from thiophene, using nickel-catalyzed Wenkert arylation, McCormack cycloaddition, asymmetric dihydro-1H-phosphole isomerization, hydrolysis, and diastereo-selective hydrogenation. Georg Thieme Verlag Stuttgart New York.
Enantioselective synthesis of phospholenes via asymmetric organocatalytic alkene isomerization
Hintermann, Lukas,Schmitz, Marco
supporting information; experimental part, p. 1469 - 1473 (2009/08/07)
An asymmetric synthesis of the 2,5-diphenylphosphol-2-ene fragment (≥95% ee) has been realized via enantioselective Cinchona-alkaloid catalyzed double bond isomerization of a meso-2,5-diphenylphosphol-3-ene amide to a 2,5-diphenylphosphol-2-ene amide (up to 83% ee), followed by enantiomeric enrichment to ≥95% ee by crystallization. The 2,5-diphenylphosphol-2-ene amide (a cyclic phosphinic acid amide) was hydrolyzed to the 2,5-diphenylphosphol-2-ene acid (a cyclic phosphinic acid) with retention of configuration at C-5.
