posted on 2021-03-29, 20:29authored byRupert
S. J. Proctor, Padon Chuentragool, Avene C. Colgan, Robert J. Phipps
Minisci-type reactions
constitute one of the most powerful methods
for building up complexity around basic heteroarenes. The most desirable
variants involve formal oxidative coupling of a C–H bond on
each partner, leading back to the simplest possible starting materials.
We herein disclose a method that enables such a coupling of linear
amides and heteroarenes with full control of enantioselectivity at
the newly formed stereocenter as well as site selectivity on both
the heteroarene and the amide. This is achieved by the use of a chiral
phosphoric acid catalyst in conjunction with diacetyl as a combined
hydrogen atom transfer reagent and oxidant. Diacetyl is directly photoexcitable,
and thus, no extraneous photocatalyst is required: an added feature
that contributes to the simplicity and practicality of the protocol.