Photocatalytic synthesis of tetra-substituted furans promoted by carbon dioxide
作者:Ya-Ming Tian、Huaiju Wang、Ritu、Burkhard König
DOI:10.1039/d1sc06403g
日期:——
compounds in carbon dioxide (CO2) atmosphere under mild conditions. It was found that CO2 could be incorporated at the diketone enolic OH position, which was key to enabling the cleavage of a C–O bond during the rearrangement of a cyclopropaneintermediate. This method allows for the same-pot construction of two isomers of the high-value tetra-substituted furan scaffold. The synthetic scope and preliminary
A Convenient Preparation of 1,4-Dicarbonyl Compounds by Ring Cleavage of Furans with Cerium(IV) Ammonium Nitrate
作者:Lucette Lepage、Yves Lepage
DOI:10.1055/s-1983-30608
日期:——
Piano-Stool Rhodium Enalcarbenoids: Application to Catalyst-Controlled Metal-Templated Annulations of Diazoenals and 1,3-Dicarbonyls
作者:Bapurao Sudam Lad、Sreenivas Katukojvala
DOI:10.1021/acscatal.8b03865
日期:2018.12.7
An electrophilic piano-stool rhodium(III)-enalcarbenoid resulted from the reaction of diazoenal with the cationic Cp*Rh-III in the presence of a 1,3-diketone. The synthetic utility of these transient carbenoids has been demonstrated in the metal-templated [3 + 2] annulation of diazoenals and 1,3-dicarbonyls, thus leading to the enal-functionalized tetrasubstituted furans. The significance of the piano-stool enalcarbenoids has been further exemplified by the mechanistically distinct, complementary Lewis acid templated [2 + 3] annulation of diazoenals and 1,3-dicarbonyls, resulting in the trisubstituted furanyl-enones and acrylates. Mechanistic investigations revealed that these annulations proceed through catalyst-dependent chemoselective activation of diazoenal by the in situ formed metal diketonates. These methodologies gave access to core structures of indeno[1,2-b]furans, tetracyclic OLED, and a pan-AKT inhibitor.
Kleinfeller; Trommsdorff, Chemische Berichte, 1938, vol. 71, p. 2448