Open Access

Ayan Das, Benedict J. Elvers, Mithilesh Kumar Nayak, Nicolas Chrysochos, Srinivas Anga, Amar Kumar, D. Krishna Rao, Tharangattu N. Narayanan, Carola Schulzke, Cem B. Yildiz, Anukul Jana

• Herein we report secondary pyrrolidin-2-ols as a source of cyclic (alkyl)(amino)carbenes (CAAC) for the synthesis of CAAC-CuI-complexes and cyclic thiones when reacted with CuI-salts and elemental sulfur, respectively, under reductive elimination of water from the carbon(IV)-center. This result demonstrates a convenient and facile access to CAAC-based CuI-salts, which are well known catalysts for different organic transformations. It further establishes secondary alcohols to be a viable source of carbenes—realizing after 185 years Dumas’ dream who tried to prepare the parent carbene (CH2) by 1,1-dehydration of methanol. Addressed is also the reactivity of water towards CAACs, which proceeds through an oxidative addition of the O−H bond to the carbon(II)-center. This emphasizes the ability of carbon-compounds to mimic the reactivity of transition-metal complexes: reversible oxidative addition and reductive elimination of the O−H bond to/from the C(II)/C(IV)-centre.