- Light-DrivenN-Heterocyclic Carbene Catalysis Using Alkylborates
-
Radical-radical coupling, the selective reaction between two different radical species, has contributed to the methodology for connecting bulky units. Light-drivenN-heterocyclic carbene (NHC) organocatalysis is recognized as a state-of-the-art methodology enabling radical-radical coupling. The catalytic process involves forming an acyl azolium intermediate from the NHC catalyst and an acyl donor, followed by single electron reduction of this key intermediate, which is largely dependent on the photoredox catalyst. We designed a radical NHC catalysis in which the direct photoexcitation of a borate to form a high reducing agent facilitated the single electron reduction event. The borate produces an alkyl radical for the single electron transfer process to accomplish the radical-radical coupling. This protocol enables cross-coupling between alkylborates and acyl imidazoles in addition to radical relay-type alkylacylations of alkenes with alkylborates and acyl imidazoles, affording ketones with a broad scope.
- Sato, Yukiya,Goto, Yamato,Nakamura, Kei,Miyamoto, Yusuke,Sumida, Yuto,Ohmiya, Hirohisa
-
p. 12886 - 12892
(2021/10/29)
-
- N-Heterocyclic Carbene-Catalyzed Radical Relay Enabling Vicinal Alkylacylation of Alkenes
-
The N-heterocyclic carbene-catalyzed radical relay enables the vicinal alkylacylation of styrenes, acrylates and acrylonitrile using aldehydes and tertiary alkyl carboxylic acid-derived redox-active esters. This protocol introduces tertiary alkyl groups and acyl groups to C-C double bonds with complete regioselectivity to produce functionalized ketone derivatives. The radical relay mechanism involves single electron transfer from the enolate form of a Breslow intermediate and radical addition of the resultant alkyl radical to the alkene followed by radical-radical coupling.
- Ishii, Takuya,Ota, Kenji,Nagao, Kazunori,Ohmiya, Hirohisa
-
supporting information
p. 14073 - 14077
(2019/10/11)
-
- Radical 1,2-Alkylarylation/Acylarylation of Allylic Alcohols with Aldehydes via Neophyl Rearrangement
-
A metal-free 1,2-alkylarylation of allylic alcohols with aliphatic aldehydes through concomitant radical neophyl rearrangement was developed, providing 1,2-diphenyl-3-alkyl propanones in moderate to good yields. Moreover, when cyclopropanecarbaldehyde and aryl carbaldehydes were concerned, acylarylation was involved leading to 1,4-dicarbonyl compounds.
- Pan, Changduo,Ni, Qingting,Fu, Yu,Yu, Jin-Tao
-
p. 7683 - 7688
(2017/07/26)
-
- Reductive alkylations involving 2°- and 3°-enolyl adduct radicals
-
Reductive tert-butylation of electronegatively substituted alkenes is readily achieved in Me2SO by reaction with excess t-BuHgCl/Et3SiH. Reactivity studies indicate that towards t-Bu. s-cis enones are more reactive than the s-trans conformers.
- Russel,Shi
-
p. 3841 - 3844
(2007/10/02)
-