Photochemical phosphorus-enabled scaffold remodeling of carboxylic acids.

The excitation of carbonyl compounds by light to generate radical intermediates has historically been restricted to ketones and aldehydes; carboxylic acids have been overlooked because of high energy requirements and low quantum efficiency. A successful activation strategy would necessitate a bathochromic shift in the absorbance profile, an increase in triplet diradical lifetime, and ease of further functionalization. We present a single-flask transformation of carboxylic acids to acyl phosphonates that can access synthetically useful triplet diradicals under visible light or near-ultraviolet irradiation. The use of phosphorus circumvents unproductive Norrish type I processes, promoting selectivity that enables hydrogen-atom transfer reactivity. Use of this strategy promotes the efficient scaffold remodeling of carboxylic acids through various annulation, contraction, and expansion manifolds.

Peng, Q., Hwang, M. U., Rentera-Gmez, . ., Mukherjee, P., Young, R. M., Qiu, Y., ... Scheidt, K. A.

Peng, Qiupeng||Hwang, Meemie U||Rentería-Gómez, Ángel||Mukherjee, Poulami||Young, Ryan M||Qiu, Yunfan||Wasielewski, Michael R||Gutierrez, Osvaldo||Scheidt, Karl A

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