Cyclopropenylcarbinol Derivatives as New Versatile Intermediates in Organic Synthesis: Application to the Formation of Enantiomerically Pure Alkylidenecyclopropane Derivatives
作者:Samah Simaan、Ahmad Masarwa、Elinor Zohar、Amnon Stanger、Philippe Bertus、Ilan Marek
DOI:10.1002/chem.200901074
日期:2009.8.24
The copper‐catalyzed carbomagnesiation (or hydrometalation) reaction of chiralcyclopropenylcarbinolderivatives, obtained by means of a kinetic resolution of secondary allylic alcohols, leads to an easy and straightforward preparation of enantiomericallypurealkylidenecyclopropanederivatives. The reaction mechanism is composed of a syn‐carbometalation followed by a syn‐elimination reaction. To gain
Rhodium(III)‐Catalyzed Enantio‐ and Diastereoselective C−H Cyclopropylation of N‐Phenoxylsulfonamides: Combined Experimental and Computational Studies
作者:Guangfan Zheng、Zhi Zhou、Guoxun Zhu、Shuailei Zhai、Huiying Xu、Xujing Duan、Wei Yi、Xingwei Li
DOI:10.1002/anie.201913794
日期:2020.2.10
Cyclopropane rings are a prominent structural motif in biologically active molecules. Enantio- and diastereoselective construction of cyclopropanes through C-H activation of arenes and coupling with readily available cyclopropenes is highly appealing but remains a challenge. A dual directing-group-assisted C-H activation strategy was used to realize mild and redox-neutral RhIII -catalyzed C-H activation
stereoselective [3,3]‐sigmatropicrearrangement leading to the corresponding alkylidene(isocyanatocyclopropanes), which could be converted into various alkylidene(aminocyclopropane) derivatives in a one‐pot manner. This transformation complements the repertoire of sigmatropicrearrangements involving cyclopropenylcarbinol derivatives and in particular, the previously reported Overman rearrangement of cyclopropenylcarbinyl