139402-34-9Relevant academic research and scientific papers
Dynamic Kinetic Resolution in Rhodium-Catalyzed Asymmetric Arylation of Phospholene Oxides
Lim, Kelvin Meng-Hui,Hayashi, Tamio
, p. 8122 - 8125 (2017)
The reaction of 2,5-dihydro-1H-phosphole 1-oxide 1 with ArB(pin) 3 in the presence of a chiral (R)-segphos-rhodium catalyst under highly basic conditions (10 equiv of KOH) gave high yields of (1S,3S)-3-arylphospholane 1-oxide 4 with high diastereoselectivity as well as high enantioselectivity. Equilibration of 1 with its 2,3-dihydro isomer 2, which is chiral and racemic, by base-catalyzed olefin isomerization followed by kinetic resolution of 2 with the chiral rhodium catalyst realized the present dynamic kinetic resolution.
Stereoselective synthesis and resolution of P-chiral phosphine chalcogenides
Pietrusiewicz, K. Michal
, p. 573 - 576 (2007/10/03)
New synthetic methods and resolution procedures securing ready access to the resolved P-chiral phosphinoylethenes, phosphinoylacetates and secondary phosphine oxides of diversified structures have been developed. The methods are based on processes employing stereoselective nucleophilic displacement at phosphorus, asymmetric deprotonation, immolative vinyl and chirality transfer from sulfur to phosphorus, chemical and enzymatic kinetic resolution, resolution via covalent diastereoisomers, as well as direct resolution of racemates by classical resolving agents and by chromatography on chiral stationary phases.
Kinetic Resolution in 1,3-Dipolar Cycloaddition of Tartaric Acid-Derived Nitrones to 2,3-Dihydro-1-phenyl-1H-phospholes. An Enantioselective Approach to the 2,2'-Coupled Pyrrolidine-Phospholane Ring System
Brandi, Alberto,Cicchi, Stefano,Goti, Andrea,Koprowski, Marek,Pietrusiewicz, K. Michal
, p. 1315 - 1318 (2007/10/02)
Enantiomerically pure five-membered ring nitrones derived from L-tartaric acid via C2-symmetric O,O'-protected 3,4-dihydroxy pyrrolidines undergo highly regio- and stereoselective cycloaddition reactions with racemic 2,3-dihydro-1-phenyl-1H-phosphole 1-oxide and 1-sulfide.In all cases formation of only two diastereomeric cycloadducts is observed and their ratio (up to 10:1) is dependent on the size of the protecting groups in the nitrone and on the extent of conversion.The tricyclic cycloadducts feature 2,2'-connection of pyrrolidine and phospholane rings and six contiguous stereogenic centers of which three are created and the one at phosphorus is kinetically resolved during the cycloaddition process.It is established that in the studied kinetic resolutions the stereoselectivity factor s=kS/kR exceeds the value of 10 (up to 14) in the most favorable cases.In a properly tuned reaction both the diastereomeric cycloadducts and the enantiomerically enriched dihydrophosphole derivative can be simultaneously obtained in satisfactory chemical and optical yields.
Nitrone Cycloadditions to 2,3-Dihydro-1-phenyl-1H-phosphole 1-Oxide. Double Asymmetric Induction and Kinetic Resolution by a Chiral Nitrone
Goti, Andrea,Cicchi, Stefano,Brandi, Alberto,Pietrusiewicz, K. Michal
, p. 1371 - 1378 (2007/10/02)
The cycloadditions of nitrones with 2,3-dihydro-1-phenyl-1H-phosphole 1-oxide give a single cycloadduct deriving from a highly diastereoselective approach of the nitrone anti to the phenyl ring of phospholene oxide.When the chiral gliceraldehyde derived nitrone is used, only two diastereoisomers are produced in 1.7:1 ratio.The structural assignment based on NMR data and X-ray analysis of the major isomer established a trans C3-C4 stereochemistry (derived from endo TS with respect to nitrone) and a C3-C4' relative stereochemistry of threo type in the major isomer and erythro in the minor one.Therefore, each enantiomer of phospholene oxide 6 gives exclusively one cycloadduct with five contiguous stereogenic centres in an established and predictable absolute configuration.The difference of reactivity of the two enantiomers allowed a partial kinetic resolution of the racemic phospholene oxide, affording (+)-(S) enantiomer with 90percent enantiomeric excess.
