Switchable construction of oxa-heterocycles with diverse ring sizes via chemoselective cyclization controlled by dibrominated compounds

Abstract

Switchable construction of oxa-heterocycles with diverse ring sizes has been developed by performing dibrominated-compound-controlled chemoselective cyclization and subsequent derivatization.

Palladium-catalyzed [4 + 3]-annulations of oxotryptamines with allyl dicarbonates: an approach toward spiro[azepane-4,3′-oxindoles]

“…Over the past decades, a variety of methods to access spirooxindoles have been reported successively. 11 Among them, however, in contrast to five- and six-membered spirooxindoles, 12 strategies for building seven-membered spirooxindoles, particularly spirooxindoles bearing an azepane moiety, are limited in number. In 2016, Enders reported an NHC-catalyzed asymmetric formal [4 + 3] cycloaddition of isatin-derived enals with in situ -formed aza- o -quinone methides to synthesize spirobenzazepinones (Scheme 1(A)).…”