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
作者:Alberto Brandi、Stefano Cicchi、Andrea Goti、Marek Koprowski、K. Michal Pietrusiewicz
DOI:10.1021/jo00085a019
日期:1994.3
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 8 = k(S)/k(R) 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.
Pietrusiewicz, K. Michal, Phosphorus, Sulfur and Silicon and the Related Elements, 1996, vol. 109, # 1-4, p. 573 - 576
作者:Pietrusiewicz, K. Michal
DOI:——
日期:——
Dynamic Kinetic Resolution in Rhodium-Catalyzed Asymmetric Arylation of Phospholene Oxides
作者:Kelvin Meng-Hui Lim、Tamio Hayashi
DOI:10.1021/jacs.7b04570
日期:2017.6.21
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