One‐Pot Synthesis of Diazirines and
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N
<sub>2</sub>
‐Diazirines from Ketones, Aldehydes and Derivatives: Development and Mechanistic Insight
Broad scope one-pot diazirine synthesis strategies have been developed using two different oxidants depending on the nature of the starting material. In all cases, an inexpensive commercial solution of ammonia (NH3) in methanol (MeOH) was employed, avoiding the difficult use of liquid ammonia. With aliphatic ketones, t-butyl hypochlorite (t-BuOCl) was found to be the best oxidant whereas it is preferable
Chiral Phosphine Lewis Bases Catalyzed Asymmetric aza-Baylis−Hillman Reaction of N-Sulfonated Imines with Activated Olefins
作者:Min Shi、Lian-Hui Chen、Chao-Qun Li
DOI:10.1021/ja0447255
日期:2005.3.1
In the aza-Baylis-Hillman reaction of N-sulfonated imines (N-arylmethylidene-4-methylbenzenesulfonamides and others) with methyl vinyl ketone, ethyl vinyl ketone, and acrolein, we found that, in the presence of a catalytic amount of chiralphosphineLewis base such as (R)-2'-diphenylphosphanyl-[1,1']binaphthalenyl-2-ol LB1 (10 mol %) and molecular sieve 4A, the corresponding aza-Baylis-Hillman adducts
Mild Darzens Annulations for the Assembly of Trifluoromethylthiolated (SCF<sub>3</sub>) Aziridine and Cyclopropane Structures
作者:Michael D. Delost、Jon T. Njardarson
DOI:10.1021/acs.orglett.1c02204
日期:2021.8.6
We report mild new annulation approaches to trisubstituted trifluoromethylthiolated (SCF3) aziridines and cyclopropanes via Darzens inspired protocols. The products of these anionic annulations, rarely studied previously, possess attractive features rendering them valuable building blocks for synthesis platforms. In this study, trisubstituted acetophenone nucleophiles bearing SCF3 and bromine substituents
Asymmetric Aza-Morita–BaylisHillman Reaction ofN-Sulfonated Imines with Activated Olefins Catalyzed by Chiral Phosphine Lewis Bases Bearing Multiple Phenol Groups
作者:Ying-Hao Liu、Lian-Hui Chen、Min Shi
DOI:10.1002/adsc.200505476
日期:2006.5
>90% ee at −20 °C or at room temperature in THF. The mechanism of this process was investigated by 31PNMRspectroscopic analysis. The phenoxide or the key enolate intermediate, which is stabilized by intramolecular hydrogen bonding with phenol groups, was observed by 31PNMR spectroscopy. Thus, the most effective bifunctional LBBA (Lewis base and Brønsted acid) phosphine-Lewis base promoter system
在的氮杂森田-BaylisHillman反应Ñ -sulfonated亚胺(Ñ -arylmethylidene -4- methylbenzenesulfonamides)与甲基乙烯基酮(MVK),乙基乙烯基酮(EVK),和丙烯醛,我们发现,通过使用催化量的在具有多个酚基的手性膦路易斯碱的基础上,可以在-20℃或室温下于THF中以> 90%ee的高收率获得相应的加合物。通过31 P NMR光谱分析研究了该过程的机理。通过31观察到通过分子内氢与酚基团的结合而稳定的酚盐或关键烯醇盐中间体1 H NMR光谱。因此,对于这种催化的,不对称的氮杂-Morita-BaylisHillman反应,已经确定了迄今为止报道的最有效的双功能LBBA(路易斯碱和布朗斯台德酸)膦-路易斯碱促进剂体系。
Dendritic Chiral Phosphine Lewis Bases‐Catalyzed Asymmetric Aza‐Morita–Baylis–Hillman Reaction of
<i>N</i>
‐Sulfonated Imines with Activated Olefins
作者:Ying‐hao Liu、Min Shi
DOI:10.1002/adsc.200700338
日期:2008.1.4
A series of polyether dendriticchiralphosphineLewisbases was synthesized, and successfully applied to the asymmetric aza-Morita–Baylis–Hillman reaction of N-sulfonated imines (N-arylmethylidene-4-methylbenzenesulfonamides) with methyl vinyl ketone (MVK), ethyl vinyl ketone (EVK), and acrolein to give the adducts in good to excellent yields along with up to 97 % ee, which are more effective than