Chiral porous organic frameworks for asymmetric heterogeneous catalysis and gas chromatographic separation
作者:Jinqiao Dong、Yan Liu、Yong Cui
DOI:10.1039/c4cc07648f
日期:——
Three chiral robust diene-based porous organic frameworks (POFs) are prepared. POF-1 is shown to be an efficient heterogeneous catalyst after metallation for asymmetric conjugation addition with up to 93% ee, and it can also function as a new chiral stationary phase for gas chromatographic separation of racemates.
A Chiral Bis-Sulfoxide Ligand in Late-Transition Metal Catalysis; Rhodium-Catalyzed Asymmetric Addition of Arylboronic Acids to Electron-Deficient Olefins
A bis-sulfoxide with a binaphthyl backbone is introduced as a readily available, chiralligand entity in late-transition metal catalysis. Ligand p-tol-BINASO [where p-tol-BINASO is 1,1‘-binaphthalene-2,2‘-diyl-bis-(p-tolylsulfoxide)] is obtained in pure form in one single synthetic step from relatively cheap, commercially available starting materials. Precatalyst [(P,R,R)-p-tol-BINASO}RhCl]2 was synthesized
it both ways: A novel class of chiral sulfoxide‐olefin ligands was synthesized from a single chiral source. These ligands were evaluated in rhodium‐catalyzed 1,4‐additions of arylboronic acids to electron‐deficient olefins, and remarkable olefin‐directed reversal of stereoselectivity (up to >99 % ee, R isomer; 98 % ee, S isomer) was observed when the reversal ligand pair L1 (branched olefin) and L2
Electronically deficient ( Rax , S , S )-F 12 -C 3 -TunePhos and its applications in asymmetric 1,4-addition reactions
作者:Shu-Bo Hu、Zhang-Pei Chen、Ji Zhou、Yong-Gui Zhou
DOI:10.1016/j.tetlet.2016.03.072
日期:2016.4
diphosphine ligand (Rax,S,S)-F12-C3-TunePhos has been concisely synthesized. The electron-poor ligand features both chiral centers and chiral axis bearing fluoro-functional groups on each phosphorus phenyl ring based on C3-TunePhos backbone. The catalyst composed of this ligand and rhodium showed excellent activities and enantioselectivities in asymmetric 1,4-addition reactions of arylboronic acids to
bidentate P-alkene ligands was observed in the presence of Lewis basic solvents, and model compounds of mono- and bis-solvated species (13, 14) were isolated. Cu formed trigonal-planar neutral (15−17) and cationic complexes (18, 19) of the general formulas [CuI(κ1P-alkene)2] and [Cu(κ1P-alkene)2BF4], respectively (P-alkene = 2, 4, 5). The cationic Rh species 11 catalyzed the 1,4-addition of arylboronic