Asymmetric synthesis of dibenzo[b,d]azepines by Cu-catalyzed reductive or borylative cyclization
A copper-catalyzed asymmetric intramolecular reductive cyclization for the synthesis of dibenzo[b,d]azepines is described. Use of 2′-vinyl-biaryl-2-imines as substrates and in situ formed [CuI/(Ph-BPE)] as the catalyst enables the synthesis of 7-membered bridged biarylamines containing both central and axial stereogenic elements in high yields (up to 98%) and with excellent diastereo- and enantioselectivities (>20 : 1 d.r., up to 99% ee). Moreover, the same catalyst was found to facilitate a related borylative cyclization to afford versatile boronic ester derivatives. Both reactions proceed under mild conditions (rt) and are applicable to a variety of substituted aromatic and heterocyclic derivatives. ; Junta de Andalucía (Grants P18-FR-3531, P18-FR-644, US1262867 and US-1260906) ; Aragon Government (Grupos E34_20R) ; Ministerio de Ciencia e Innovación (Grants PID2019-106358GB-C21, PID2019-106358GB-C22, PID2019-104090RB-100)