RESUMO
A new strategy is reported for intramolecular Buchner-type reactions using PIDA as a promotor. Traditionally, the Buchner reaction is achieved via Rh-carbenoids derived from RhII catalysts with diazo compounds. Herein, the first metal-free Buchner-type reaction to construct highly strained cycloheptatriene- and cyclopropane-fused lactams is presented. The advantage of these transformations is in their mild reaction conditions, simple operation, broad functional group compatibility and rapid synthetic protocol. In addition, scaled-up experiments and a series of follow-up synthetic procedures were performed to clarify the flexibility and practicability of this method. DFT calculations were carried out to clarify the mechanism.
RESUMO
The general protocol for the synthesis of isoxazolidine-fused isoquinolin-1(2H)-ones was established with the help of bench stable hypervalent iodine reagent PIDA. Polycyclic six-, seven- and eight-membered N-heterocycles can be rapidly synthesized from available amides under metal-free conditions within 1 min at room temperature through C-H/N-H functionalization. Moreover, the protocol has the merits of broad substrate scope, atom economy and operational simplicity.
RESUMO
An unprecedented synthesis of valuable benzofuran-3(2 H)-one scaffolds with a quaternary center was developed via Rh/Co relay catalyzed C-H functionalization/annulation of N-aryloxyacetamides with propiolic acids in moderate to good yields. The reaction features the simultaneous construction of the benzofuran motif containing a C2 quaternary center and a C3 carbonyl group. The preliminary mechanism study verified that the O atom of C3 carbonyl group originates from molecular oxygen.
