678195-41-0Relevant academic research and scientific papers
Borane catalysed cyclopropenation of arylacetylenes
Dasgupta, Ayan,Heard, Matthew J.,Melen, Rebecca L.,Stefkova, Katarina
supporting information, p. 6736 - 6739 (2021/07/13)
Triarylboranes have gained substantial attention as catalysts for C-C bond forming reactions due to their remarkable catalytic activities. Herein, we report B(C6F5)3catalysed cyclopropenation of a wide variety of arylacetylenes using donor-acceptor diazoesters. A mild reaction protocol has been developed for the synthesis of functionalised cyclopropenes (33 examples) in good to excellent yields.
Blue light-promoted cyclopropenizations of N-tosylhydrazones in water
Yan, Kaichuan,He, Hua,Li, Jianglian,Luo, Yi,Lai, Ruizhi,Guo, Li,Wu, Yong
supporting information, p. 3984 - 3987 (2021/06/15)
Carbene transfer reactions play an important role in the field of organic synthesis because of their ability to construct a variety of molecules. Herein, we reported on blue light-induced cyclopropenizations of N-tosylhydrazones in water, which avoids the use of expensive metal-based catalysts and toxic organic solvents. This metal-free and operationally simple methodology enable highly efficient cyclopropenizations, X-H insertion reactions, and cyclopropanation under mild reaction conditions.
Blue-Light-Induced Carbene-Transfer Reactions of Diazoalkanes
Hommelsheim, Renè,Guo, Yujing,Yang, Zhen,Empel, Claire,Koenigs, Rene M.
supporting information, p. 1203 - 1207 (2019/01/04)
Carbenes are very important reactive intermediates to access a variety of complex molecules and are applied widely in organic synthesis and drug discovery. Typically, their chemistry is accessed by the use of transition metal catalysts. Herein, we describe the application of low-energy blue light for the photochemical generation of carbenes from donor–acceptor diazoalkanes. This catalyst-free and operationally simple approach enables highly efficient cyclopropenation reactions with alkynes and the rearrangement of sulfides under mild reaction conditions, which can be utilized for both batch and continuous-flow processes.
An efficient and general method for resolving cyclopropene carboxylic acids
Liao, Lian-An,Zhang, Fan,Yan, Ni,Golen, James A.,Fox, Joseph M.
, p. 1803 - 1816 (2007/10/03)
A general method is described for the resolution of cycloprop-2-ene carboxylic acids via diastereomeric N-acyloxazolidines prepared from enantiomerically pure oxazolidinones. Although a number of oxazolidinones were shown to resolve cyclopropene carboxylic acids, the oxazolidinones of S-phenylalaninol, S-phenylglycine and (1S,2R)-cis-1-amino-2-indanol are optimal in terms of resolving power and cost effectiveness. Separations were performed using simple flash chromatography, and because there is typically a large difference in Rf values it is possible to separate gram quantities of pure diastereomers in a single chromatogram. The cycloprop-2-ene carboxylic acids that can be resolved include those that are substituted at the 1-position by H, Ph, α-naphthyl, CO2Me, CH2OMOM, and trans-styryl; alkene substituents include Me, n-alkyl, Ph and tethered alkynes. Remarkably, 2-methyl-3-propylcycloprop-2-ene carboxylic acid can also be resolved with ease. The relative configurations of four diastereomerically pure oxazolidines were determined by X-ray crystallography. Reduction of the N-acyloxazolidinones with LiBH4 give enantiomerically pure derivatives of 3-hydroxymethylcyclopropene that react with either MeMgCl or vinylMgCl and catalytic CuI to give enantiomerically pure products of syn-addition.
