Visible-light-induced metal-free trifluoromethylation of activated, carbocyclic, and unactivated vinylcyclopropanes via a ring-opening reaction using the Langlois reagent (CF 3 SO 2 Na) is reported to synthesize allylic trifluoromethylated derivatives. Allylic trifluoromethylation was achieved by a photo-oxidative single electron transfer (SET) process at an ambient temperature and under metalfree conditions and visible-light irradiation using pyrylium salt as a photoredox catalyst. The reported methodology has an operational simplicity, broad substrate scope, high functional group tolerance, and scalability.
A visible-light-driven
organophotocatalyzed multicomponent approach
has been developed for tandem direct C(sp3)–H activation
and alkylation followed by trifluoromethylthiolation in a one-pot
operation. We report a completely metal-free, tandem, three-component
approach for the difunctionalization of activated alkenes via the
photoinduced radical pathway. This protocol allows the formation of
two new C(sp3)–C(sp3) and C(sp3)–SCF3 bonds using a bench-stable, easy-to-handle
trifluoromethylthiolating reagent under mild reaction conditions.
The generosity of this reaction is shown with a library of C(sp3)–H donors and alkenes derivatives. The reaction conditions
can tolerate a wide variety of functional groups. Gram-scale synthesis
using environmentally benign and straightforward conditions highlights
the synthetic advancement of the methodology. Further functionalization
of the final product is also successfully demonstrated.
Selective synthesis of three different bioactive heterocycles; isoxazolines, 5‐hydroxy‐2‐isoxazolines and isoxazoles from the same starting material using TEMPO (2,2,6,6‐Tetramethylpiperidin‐1‐oxyl) as a radical initiator is reported. Selectivity was achieved using different oxidants with TEMPO. The reaction goes through a 1,5‐HAT (hydrogen atom transfer) process resulting in products with good yields. This strategy offers a straightforward route to three different heterocycles from oximes via radical‐mediated C(sp3)‐H oxidation.
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