LAUSR

An intensified and scalable continuous flow process is presented for the hydroxylation of enolizable tertiary ketones. The procedure relies on molecular oxygen, metal-free conditions and a low toxicity solvent (DMSO). The reaction is optimized on the microfluidic scale with a model ketone substrate (isobutyrophenone) and next extended to a small library of structurally diverse enolizable ketones. High conversion and selectivity are achieved under extremely short residence time. A DFT computational study provides insights on the mechanism and selectivity on various substrates. The scalability of the hydroxylation step is next assessed in a commercial pilot scale continuous flow SiC reactor, hence providing up to 12.5 kg per day of industrially relevant α-ketols with applications ranging from Type I radical photoinitiators to intermediates for the preparation of active pharmaceutical ingredients. Graphical abstract Details of the Corning® Advanced-Flow™ G1 SiC reactor (Courtesy of Corning®) utilized for the intensified continuous flow hydroxylation of tertiary ketones with molecular oxygen.