Intramolecular photo[4+2]cycloaddition of an enone with a benzene ring

Kishikawa, Keiki; Akimoto, Satoshi; Kohmoto, Shigeo; Yamamoto, Makoto; Yamada, Kazutoshi

doi:10.1039/a601710j

Cited by 31 publications

(20 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Inspired by the pioneering studies of UV-mediated benzenoid arenes dearomatization, as introduced by Kohmoto and co-workers, 37 we started our investigation by examining the reactivity of pyridine-containing cinnamyl amides under visible-light-sensitized conditions. In the presence of the heterogeneous photocatalyst [Ir-F]@polymer (1.5 mol%), after irradiation for 5 h with blue LEDs (6 W, l max = 455 nm) in acetone, an N-cinnamoyl picolinamide 4a was fully converted to the dearomative [4+2] cycloaddition product 5a in an excellent yield of 99% with 2:1 dr (Table 1, entry 1).…”

Section: Dearomatization Reaction Evaluationmentioning

confidence: 99%

Direct Dearomatization of Pyridines via an Energy-Transfer-Catalyzed Intramolecular [4+2] Cycloaddition

Strieth‐Kalthoff

Dalton

et al. 2019

Chem

View full text Add to dashboard Cite

The catalytic dearomatization of pyridines, accessing medicinally relevant N-heterocycles, is of high interest. Currently direct, dearomative strategies rely generally on reduction or nucleophilic addition, thus limiting the architecture of the dearomatized products to a six-membered ring. We herein introduce a catalytic, dearomative cycloaddition reaction with pyridines using photoinduced energy transfer catalysis, thereby advancing dearomatization methodology and increasing the topology of pyridine dearomatization products. This unprecedented method features high yields, broad substrate scope (44 examples), excellent functional group tolerance, and facile scalability. Furthermore, a recyclable and sustainable polymer immobilized photocatalyst was employed. Computational and experimental investigations support a mechanism in which a cinnamyl moiety is promoted to its corresponding excited triplet state through visible-light-mediated energy transfer catalysis, followed by a regioselective and dearomative [4+2] cycloaddition to pyridines. This work demonstrates the contribution of visible light catalysis toward enabling thermally challenging organic transformations.

show abstract

Section: Dearomatization Reaction Evaluationmentioning

confidence: 99%

Direct Dearomatization of Pyridines via an Energy-Transfer-Catalyzed Intramolecular [4+2] Cycloaddition

Strieth‐Kalthoff

Dalton

et al. 2019

Chem

View full text Add to dashboard Cite

show abstract

“…There are few examples leading to para products in high yield. However, one example is the intramolecular photocycloaddition of a cinnamoylamide and a benzamide moiety ( Scheme 32 ) [ 97 ]. This reaction is very efficient and leads to high yields of the bicyclo[2.2.2]octadiene derivative.…”

Section: Reviewmentioning

confidence: 99%

The arene–alkene photocycloaddition

Streit¹,

Bochet²

2011

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

show abstract

“…Rigaku AFC-7S Mercury diffractometer Absorption correction: multi-scan (Jacobson, 1998) T min = 0.897, T max = 0.985 (expected range = 0.850-0.934) 32660 measured reflections 5802 independent reflections 3687 reflections with I > 2(I) R int = 0.063 Refinement R[F 2 > 2(F 2 )] = 0.070 wR(F 2 ) = 0.161 S = 1.07 5802 reflections 362 parameters H-atom parameters constrained Á max = 0.18 e Å À3 Á min = À0.28 e Å À3 Absolute structure: Flack (1983), 1693 Friedel pairs Flack parameter: À0.03 (9) et al, 2003), phenyl-substituted amides with antioxidant and anti-inflamatory activity as novel lipoxygenase inhibitor (Pontiki & Hadjipavlou, 2007), and also as precursor for photochemical studies (Kishikawa et al, 1997).…”

Section: Data Collectionmentioning

confidence: 99%