Acid-catalyzed allenylation of pyrazolones with propargyl alcohols
作者:Wande Zhang、Shiqiang Wei、Jingping Qu、Baomin Wang
DOI:10.1039/d1ob00592h
日期:——
A TsOH-catalyzed allenylation of pyrazolones with propargylic alcohols has been developed. The established reaction system is well tolerated by a wide scope of pyrazolones and propargylic alcohols. The process has the salient features of operational simplicity, facile scale-up and high yield. In particular, the integration of the pharmaceutical-related pyrazolone skeleton and the allenyl group into
Catalytic asymmetric construction of C-4 alkenyl substituted pyrazolone derivatives bearing multiple stereoelements
作者:Wande Zhang、Shiqiang Wei、Wenyao Wang、Jingping Qu、Baomin Wang
DOI:10.1039/d1cc01123e
日期:——
An organocatalyticasymmetric process was reported for the sterically precise construction of C-4 alkenyl substituted pyrazolone derivatives bearing multiple stereoelements. A series of interesting products featuring the union of a centrally chiral pyrazolone moiety and an axially chiral styrene unit were obtained in high yield with excellent diastereoselectivity and enantioselectivity (up to 99% ee
Isothiourea-catalysed enantioselective Michael addition of N-heterocyclic pronucleophiles to α,β-unsaturated aryl esters
作者:Chang Shu、Honglei Liu、Alexandra M. Z. Slawin、Cameron Carpenter-Warren、Andrew D. Smith
DOI:10.1039/c9sc04303a
日期:——
The isothiourea-catalysed enantioselective Michaeladdition of 3-aryloxindole and 4-substituted-dihydropyrazol-3-one pronucleophiles to α,β-unsaturated p-nitrophenyl esters is reported. This process generates products containing two contiguous stereocentres, one quaternary, in good yields and excellent enantioselectivities (>30 examples, up to > 95 : 5 dr and 99 : 1 er). This protocol harnesses the
2-arylbenzimidazolines (8), generated in situ from o-phenylenediamine (7) and the appropriate arylaldehydes, by reaction with 4-arylmethylenepyrazol-5-ones (1) or isoxazol-5-ones (2) produce the 4-arylmethylderivatives (3) or (4) and the C,C- (5) or the C,N-linkeddimers. The reaction was rationalised on the basis of the role of 2-arylbenzimidazoline as a reducing agent and proceeds by a non-chain
Direct Allylic C–H Bond Activation To Synthesize [Pd(η<sup>3</sup>-cin)(IPr)Cl] Complex: Application in the Allylation of Oxindoles
作者:Rong-Bin Hu、Chun-Hai Wang、Wei Ren、Zhong Liu、Shang-Dong Yang
DOI:10.1021/acscatal.7b02965
日期:2017.11.3
an efficient ligand in promoting allylic C–Hbond functionlizations. Notably, the catalytic [Pd(η3-cin)(IPr)Cl] complex (where cin = cinnamyl) was formed in situ from direct C–Hactivation of allylic precursors, and was obtained by way of one-pot strategy with available IPr·HCl and allylbenzene. The catalyst exhibits high regioselectivity and stereoselectivity of the allylic C–H alkylation with oxindoles