Cobalt-Catalyzed Annulation of Salicylaldehydes and Alkynes to Form Chromones and 4-Chromanones
作者:Junfeng Yang、Naohiko Yoshikai
DOI:10.1002/anie.201510999
日期:2016.2.18
A unique cobalt(I)–diphosphine catalytic system has been identified for the coupling of salicylaldehyde (SA) and an internal alkyne affording a dehydrogenative annulation product (chromone) or a reductive annulation product (4‐chromanone) depending on the alkyne substituents. Distinct from related rhodium(I)‐ and rhodium(III)‐catalyzed reactions of SA and alkynes, these annulation reactions feature
Decarbonylative/decarboxylative [4 + 2] annulation of phthalic anhydrides and cyclic iodoniums towards triphenylenes
作者:Lingyu Huang、Rongrong Xie、Chaoying Wen、Yanyan Yang、Yiwen Wang、Shiyan Ren、Bin Huang、Shiqing Li
DOI:10.1039/d2ob00500j
日期:——
A palladium-catalyzed decarbonylative/decarboxylative annulation of phthalic anhydrides with cyclic diaryliodonium salts to synthesize triphenylenes has been developed.
efficient photo-induced transition-metal-free direct hydrogen evolution and annulation of 2,3-diphenyl-4H-chromen-4-ones in EtOH–H2O (19 : 1, v/v) at room temperature was described. The reported methodology provided a quick and easy access to the synthesis of dibenzo[a,c]xanthen derivatives, which eliminates the use of any catalysts, oxidants and additives.