Copper Photocatalyzed Divergent Access to Organic Thio- and Isothiocyanates

We disclose a copper-photocatalyzed strategy that enables
selective
access to organic thiocyanates and isothiocyanates using benzylic
thiocyanates as ATRA reagents. The electronic nature of the aromatic
system is a crucial factor defining the outcome of the reaction for
forging either the kinetic C–S or the thermodynamic C–N
bonds. Mechanistic investigations support a radical pathway initiated
by a reductive C–S bond cleavage of the substrates followed
by a divergent inner-/outer-sphere interaction with copper depending
on the electronic density of the formed intermediates. The developed
protocol proceeds with high regio- and chemoselectivity and can also
be applied for late-stage functionalization of bioactive molecules.
The utility of the products is highlighted by their facile conversion
to several building blocks that are relevant to organic synthesis.