Rh(III)-catalyzed C-H activation/cyclization of benzamides and diazo compounds to form isocoumarins and α-pyrones
Rhodium-catalyzed intermolecular cyclization of benzamides and diazo compounds via C-H activation has been achieved to construct C-C/C-O bonds for the first time. The process provides a facile approach for the construction of isocoumarins and α-pyrones wi
Rh(III)-catalyzed annulation of BOC-protected benzamides with diazo compounds: Approach to isocoumarins
A mild rhodium-catalyzed annulation of Boc-protected benzamides with diazo compounds via C?C/C?O bond formation has been explored. In the presence of [Cp*RhCl2]2, AgSbF6 and Cs2CO3, Boc-protected benzamides can be effectively annulated to yield isocoumarins in 0.5–2 h.
Dong, Guangyu,Li, Chunpu,Liu, Hong
(2019/04/02)
Synthesis of isocoumarins via silver(I)-mediated annulation of enol esters
Silver-mediated annulation of 2-iodo enol esters leading to 4- and 3,4-substituted isocoumarins was accomplished selectively at room temperature. Coupling of 2-iodo benzoic acids with enolates that were produced in situ from the simple esters was also performed to produce isocoumarins under analogous reaction conditions. Owing to the mildness of the current protocol, 4-acyl 3-substituted isocoumarins were efficiently produced without any deacylation.
Ortho-Induced transition-metal-free C-arylation cyclization reaction for the synthesis of polysubstituted isocoumarins
A new protocol for the synthesis of polysubstituted isocoumarins from 2-iodobenzoic acid and β-diketone compounds has been developed. The occurrence of C-arylation cyclization reaction in transition-metal-free systems and ortho-induced substrates has been exploited. Reactions using these inexpensive conditions have displayed high functional group tolerance and excellent yields.