Divergent reactivity of phenol- and anisole-tethered donor-acceptor α-diazoketones

The first study of the divergent reactivity of phenol/anisole-tethered donor-acceptor α-diazoketones is described. Four distinct product classes were shown to be accessible from closely related α-diazoketone precursors, with the reaction outcome dependent on the nature of the oxygen substituent on the phenol/anisole ring and the catalyst used to decompose the diazo group. Anisole and TBS-protected derivatives selectively produce three products types (cyclopropanes, tetralones and 1,2-dicarbonyls) while phenols selectively produce spirocyclic dienones.