Generation and reactivity of phenylhydroxycarbenes in solution

Abstract We provide evidence for the first successful generation of phenylhydroxycarbene and 4‐trifluoromethylphenylhydroxycarbene in solution. The carbene tautomers of the corresponding benzaldehyde derivatives had been prepared under cryogenic matrix‐isolation conditions before but their reactivity, apart from a prototypical quantum mechanical tunneling [1,2]‐H‐shift reaction, had not been studied. Here our strategy is to employ suitable carbene precursors for the McFadyen–Stevens reaction, to generate the parent and the para ‐CF 3 ‐substituted phenylhydroxycarbenes, and to react them with benzaldehyde or acetone in a highly facile, allowed six‐electron carbonyl‐ene reaction toward the corresponding α‐hydroxy ketones. Our findings are supported by computations at the DLPNO‐CCSD(T)/cc‐pVQZ//B3LYP/def2‐TZVP level of theory.