Cu-catalyzed coupling-cyclization in PEG 400 under ultrasound: a highly selective and greener approach towards isocoumarins
作者:R. Gangadhara Chary、G. Rajeshwar Reddy、Y. S. S. Ganesh、K. Vara Prasad、S. K. Phani Chandra、Soumita Mukherjee、Manojit Pal
DOI:10.1039/c3ra40969d
日期:——
The combination of CuI–K2CO3-PEG 400 facilitated the coupling-cyclization of o-iodobenzoic acid with terminal alkynes under ultrasound, affording a greener and practical approach towards 3-substituted isocoumarins with remarkable regioselectivity. This inexpensive and Pd and ligand free methodology gave rise to various isocoumarins of potential pharmacological interest.
An efficient method for the synthesis of 3-substituted isocoumarins that are an important class of biologically active scaffolds via annulation of 2-bromobenzoic esters with terminal alkynes by copper catalyzed is described. The advantages of this method include mild reaction conditions, high yield and regioselectivity, and wide tolerance toward functional groups.
Gold-Catalyzed Cascade Annulations of 2-(Ynol)aryl Aldehydes: Facile Synthesis of Benzochromanes and Benzobicyclo[<i>n</i>.3.1]acetals
作者:Le-Ping Liu、Gerald B. Hammond
DOI:10.1021/ol101985d
日期:2010.10.15
Gold-catalyzed reactions of 2-(ynol)aryl aldehydes were investigated. Benzochromanes were obtained from the reaction when AuCl3 was employed as the catalyst, whereas benzobicyclo[n.3.1]acetals were produced when triazole−gold was employed as the catalyst. Plausible mechanisms are discussed.
研究了金催化的2-(ynol)芳基醛的反应。当使用AuCl 3作为催化剂时,从反应中获得苯并二氢吡喃,而当使用三唑-金作为催化剂时,则生成苯并双环[ n .3.1]缩醛。讨论了可能的机制。
Regioselective Synthesis of Benzannulated [5,6]-Oxaspirolactones via Cu(II)-Catalyzed Cycloisomerization of 2-(5-Hydroxyalkynyl)benzoates
作者:Sagar S. Thorat、Sagar P. Shimpi、Pooja I. Sambherao、Gamidi Rama Krishna、Ravindar Kontham
DOI:10.1021/acs.joc.3c01751
日期:2023.12.15
Cu(II)-catalyzed cascade cycloisomerization of 2-(5-hydroxyalkynyl)benzoates, enabling the regioselective synthesis of benzannulated [5,6]-oxaspirolactones containing an isochromen-1-one moiety. This strategy offers a rapid and efficient approach to access a diverse array of benzannulated [5,6]-oxaspirolactones. The methodology presented here showcases a broad substrate scope, delivering good yields
Ready Access to Benzannulated [5,5]-Oxaspirolactones Using Au(III)-Catalyzed Cascade Cyclizations
作者:Yash Mankad、Sagar S. Thorat、Pronay Das、Gamidi Rama Krishna、Ravindar Kontham、D. Srinivasa Reddy
DOI:10.1021/acs.joc.1c02843
日期:2022.3.4
showcases an unprecedented Au(III)-catalyzed cascade cyclization of 2-(4-hydroxyalkynyl)benzoates to access benzannulated [5,5]-oxaspirolactones related to biologically active natural products. This reaction proceeds through an initial 5-endo-dig mode of hydroalkoxylation of the alkynol segment to give the oxocarbenium species (via cyclic enol-ether) followed by the addition of carboxylate onto the oxocarbenium