Visible Light-Mediated Coupling of α-Bromochalcones with Alkenes
作者:Suva Paria、Viktor Kais、Oliver Reiser
DOI:10.1002/adsc.201400638
日期:2014.9.15
Photoredox catalyzed intermolecular couplings of α‐bromochalcones to olefins have been developed. Employing 1 mol% of the iridium complex Ir(ppy)3 as photocatalyst, vinyl radicals are generated from α‐bromochalcones as the key intermediate, which efficiently engage in a formal [4+2] cyclization with various alkenes. The resulting 3,4‐dihydronaphthalenes can be readily transformed to the corresponding
已经开发了光氧化还原催化的α-溴代查耳酮与烯烃的分子间偶联。使用1 mol%的铱络合物Ir(ppy)3作为光催化剂,乙烯基自由基是由α-溴代查耳酮作为关键中间体生成的,可以有效地与各种烯烃进行正式的[4 + 2]环化反应。生成的3,4-二氢萘可以很容易地转化为相应的萘,并进一步环化为5 H-苯并[ c ]芴。另外,如果烯烃在烯丙基位置具有合适的离去基团,则可以得到Heck型偶联产物与空间受阻更强的烯烃或烯丙基化产物。
Chiral N,N′-dioxide-Sc(NTf<sub>2</sub>)<sub>3</sub> complex-catalyzed asymmetric bromoamination of chalones with N-bromosuccinimide as both bromine and amide source
A chiral N,N[prime or minute]-dioxide-Sc(NTf2)3complex catalytic system has been developed to catalyze the asymmetric bromoamination reaction of chalones with N-bromosuccinimide.
Visible Light Photoredox Catalyzed Cascade Cyclizations of α-Bromochalcones or α-Bromocinnamates with Heteroarenes
作者:Suva Paria、Oliver Reiser
DOI:10.1002/adsc.201301069
日期:2014.2.10
AbstractVinyl radicals were generated from α‐bromochalcones or α‐bromocinnamate ethyl ester under visible light photoredox catalyzed conditions via an oxidative quenching cycle of the iridium complex [IrdF(CF3)ppy}2(dtbbpy)]PF6 and subjected to cascade cyclizations with heteroarenes entailing two consecutive CC bond formations and three CH activations. The process is amenable to furans, benzofurans, pyrroles, and indoles, giving rise to a broad variety of novel polycyclic frameworks in high yields under mild and environmentally benign reaction conditions.magnified image