Chemo- and regioselective benzylic C(sp3)–H oxidation bridging the gap between hetero- and homogeneous copper catalysis

Conformational studies of biaryl-bridged seven-membered lactones with a quaternary carbon center

We show the synthesis and conformational studies of a series of 7,7-disubstituted-dibenzo[b,d]oxepin-6(7H)-ones that feature biaryl-bridged seven-membered lactones with a quaternary carbon center, in which the larger substituents prefer the axial positions. Further studies on the crystal structures and DFT calculations revealed that the high selectivity observed is attributed to the volume of substituents.

Protocol for chemo- and regioselective C(sp3)-H activation using a heterogeneous copper powder-catalyzed reaction

Here, we present a protocol for the synthesis of dibenzo[c,e]oxepin-5(7H)-ones starting from 2'-alkyl-[1,1'-biphenyl]-2-carboxylic acids. This technique uses two copper(0)-catalyzed benzylic C(sp³)-H activation strategies taking either di-tertbutyl peroxide or gaseous oxygen as an oxidant. We detail a photocatalytic thermal approach for copper powder-catalyzed reaction with oxygen. We also describe a procedure for catalyst recycling in both the strategies. The product has been successfully synthesized both in mmol and gram scale. For complete details on the use and execution of this protocol, please refer to Nandi et al. (2022).