Visible‐Light‐Induced Cleavage of C−S Bonds in Thioacetals and Thioketals with Iodine as a Photocatalyst

Abstract

The front cover artwork is provided by Matthias Krumb and Sarah Susanne Part. It symbolizes the conversion of a dithiane to a ketone through joint activation of oxygen, iodine, and light. This process cracks the C–S bonds and leads to the formation of the desired ketone. Read the full text of the Communication at 10.1002/cptc.201900231.

Photocatalytic Cleavage of Trityl Protected Thiols and Alcohols

“…Consequently, photoredox catalysis also provides opportunities for the development of new methods to cleave established protective groups. For example, single electron oxidation of dithioacetals by an excited photocatalyst, such as methylene green, 11 eosin Y, 12 a triphenylpyrylium (TPP + ) salt, 13 or I 2 14 triggers a series of events that result in the formation­ of the corresponding aldehydes or ketones (Scheme 1 A). Similarly, single electron oxidation induces deprotection of para -methoxybenzyl (PMB) ethers using Ir[dF(CF 3 )ppy] 2 (dtbbpy)PF 6 , 15 eosin Y, 16 or mesityl-10-methylacridinium (Mes-Acr + -Me) perchlorate 17 as photocatalysts in combination with a stoichiometric oxidant and a H-atom acceptor (Scheme 1 B).…”