Rhodium(III)-catalyzed intermolecular [3+3] annulation of benzoxazines with quinone compounds: access to spiro-heterocyclic scaffolds

Authors：Wei, Qing-Yi; Zhou, Ze; Yao, Meng-Lian; Liu, Ji-Kai; Wu, Bin; Yang, Jin-Ming^*

Source：Chemical Communications, 2023, 59(77): 11520-11523.

DOI：10.1039/d3cc03609j

• BOND FORMATION
• C-C
• KETIMINES

A rhodium(iii)-catalyzed redox-neutral spiroannulation approach to access the spiro[benzo[b][1,4]oxazine-benzo[c]chromene skeleton is described in this contribution. A variety of spiro[5.5]-heterocyclic scaffolds were obtained in moderate to excellent yields under mild conditions. Key features of this protocol are good substrate scope, silver-free conditions, low catalyst loadings, easy handling under air and 100% atom economy. Furthermore, scale-up reactions and late-stage derivatizations highlight the potential synthetic utility of this methodology.