Development of Gold-catalyzed [4+1] and [2+2+1]/[4+2] Annulations between Propiolate Derivatives and Isoxazoles
作者:Rajkumar Lalji Sahani、Rai-Shung Liu
DOI:10.1002/anie.201610665
日期:2017.1.19
new gold‐catalyzed annulations of isoxazoles with propiolates have been developed. Most isoxazoles follow an initial O attack on the alkyne to afford a [4+1] annulation product. This process results in a remarkable alkyne cleavage of initial propiolates. Unsubstituted isoxazoles proceed through an N attack step to yield formal [2+2+1]/[4+2] annulation products. These two annulation products arise initially
Gold-catalyzed formal [4π+2π]-cycloadditions of tert-butyl propiolates with aldehydes and ketones to form 4H-1,3-dioxine derivatives
作者:Somnath Narayan Karad、Wei-Kang Chung、Rai-Shung Liu
DOI:10.1039/c5cc04538j
日期:——
Novel gold-catalyzed [4π+2π]-cycloadditions of tert-butyl propiolates with aldehydes and ketones have been developed to form 4H-1,3-dioxine derivatives.
Gold-Catalyzed Michael-Type Reactions and [4 + 2]-Annulations between Propiolates and 1,2-Benzisoxazoles with Ester-Directed Chemoselectivity
作者:Yashwant Bhaskar Pandit、Rajkumar Lalji Sahani、Rai-Shung Liu
DOI:10.1021/acs.orglett.8b02663
日期:2018.11.2
This work reports gold-catalyzed reactions between 1,2-benzisoxazoles and propiolate derivatives with ester-controlled chemoselectivity. For ethyl propiolates 1′, their gold-catalyzed reactions afforded Michael-type products 4, whereas tert-butyl propiolates 1 preferably underwent [4 + 2]-annulations, further yielding 6H-1,3-oxazin-6-one derivatives 3.
这项工作报告了1,2-苯并恶唑与丙酸酯衍生物之间的金催化反应,并具有酯控制的化学选择性。对于丙酸乙酯1',其金催化的反应得到迈克尔型产物4,而丙酸叔丁酯1优选经历[4 + 2]环化,进一步产生6 H -1,3-恶嗪-6-一衍生物3。
Copper- or Phosphine-Catalyzed Reaction of Alkynes with Isocyanides. Regioselective Synthesis of Substituted Pyrroles Controlled by the Catalyst
The copper-catalyzed reaction of isocyanides (CNCH(2)EWG(1)) 1 with electron-deficient alkynes (RC equivalent to CEWG(2)) 2 gave the 2,4-di-EWG-substituted pyrroles 3 selectively, whereas the phosphine-catalyzed reaction of 1 with 2 afforded the 2,3-di-EWG-subsituted pyrroles 4. Accordingly, regioselective synthesis of substituted pyrroles has been achieved by merely choosing the catalyst.
Nasarow; Kuwarsina, Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1938, p. 678