Cobalt-catalyzed chemoselective dehydrogenation through radical translocation under visible light

Abstract

The transformations that allow the direct removal of hydrogen from their corresponding saturated counterparts by dehydrogenative strategy is a dream reaction that has remained largely underexplored. In this report, a...

Photoexcited Palladium-Initiated Remote Desaturation of N-Alkoxypyridinium Salts

“…On the basis of these aforementioned mechanistic studies and relevant literatures, ,, a plausible radical chain mechanism for the radical remote desaturation is proposed in Figure . The Pd(0) complex is excited by blue light.…”

“…Remote directing desaturation through hydrogen atom transfer (HAT) process provides a new route for regioselective introduction of a CC double bond into alkanes. Baran and co-workers reported a remote desaturation reaction through highly reactive aryl radicals by oxidation of aryl triazenes . With the rapid development of photochemistry, chemical transformations which are difficult to be achieve in ground state metals have been greatly developed using excited state metals .…”

Autocatalytic photoinduced oxidative dehydrogenation of pyrido[2,3-d]pyrimidin-7(8H)-ones: synthesis of C5–C6 unsaturated systems with concomitant formation of a long-lived radical

“…At this point, it is necessary to highlight that this photoinduced oxidative dehydrogenation of 5,6-dihydropyrido[2,3-d] pyrimidin-7(8H)-one 11a is, to the best of our knowledge, the first case in which the dehydrogenation takes place without the presence of an extra photosensitizer component or metals. 13,14 In fact, according to the work of Sadhu et al, 15 most of the dehydrogenating methods use strong oxidants (H 2 SO 4 , HNO 3 , CrO 3 -acetic acid, DDQ, or MnO 2 ), NBS-peroxide assisted oxidation, or metal catalysts (Cu(OAc) 2 -Pb(OAc) 4 and Pd-C). Their photochemical dehydrogenation using oxygen and a photoinduced electron transfer (PET) sensitizer (9-cyanoanthracene, 9-cyanophenanthrene, or 1-cyanonaphthalene) is the only precedent of our autocatalytic process.…”

Chiral Trifluoromethylated Enamides: Synthesis and Applicability

“…54 Recently, the groups of Maulide, Jiao and Xu presented a more direct approach by N-dehydrogenation of amides, which either requires strong oxidative conditions or superstoichiometric amounts of reagents and is limited to tertiary enamides. [55][56][57] Currently, synthetic strategies to access enamides with a stereogenic center, especially at the more challenging C𝛾-position, are scarce and the field is underexplored. Nevertheless, such compounds seem to be of interest as demonstrated by recent examples for the syntheses of axially chiral enamides.…”