Photo-Organocatalytic Enantioselective Radical Cascade Reactions of Unactivated Olefins
作者:Pablo Bonilla、Yannick P. Rey、Catherine M. Holden、Paolo Melchiorre
DOI:10.1002/anie.201808183
日期:2018.9.24
Radical cascade processes are invaluable for their ability to rapidly construct complex chiral molecules from simple substrates. However, implementing catalytic asymmetric variants is difficult. Reported herein is a visible‐light‐mediated organocatalytic strategy that exploits the excited‐state reactivity of chiral iminium ions to trigger radical cascade reactions with high enantioselectivity. By combining
hydroacyloxylation of unactivated alkenes, offering a streamlined access to relevant γ-lactones, which features the utilization of either a calcium(II) salt or triflimide as a catalyst in hexafluoroisopropanol. This method could be applied to the synthesis of natural products and the late-stage functionalization of natural and bioactive molecules. Additionally, DFT computations were used to elucidate the twist
On the understanding of BF<sub>3</sub>·Et<sub>2</sub>O-promoted intra- and intermolecular amination and oxygenation of unfunctionalized olefins
作者:Chun-Hua Yang、Wen-Wen Fan、Gong-Qing Liu、Lili Duan、Lin Li、Yue-Ming Li
DOI:10.1039/c5ra10513g
日期:——
for both intra- and intermolecular amination and oxygenation of unfunctionalized olefins. In the presence of 3 equiv. of BF3·Et2O, intramolecular hydroamination of N-(pent-4-enyl)-p-toluenesulfonamides, N-(hex-5-enyl)-p-toluenesulfonamides, intermolecular hydroamination between sulfonamides and cyclohexene, norbornene or styrene, lactonization of pent-4-enoic acid or hex-5-enoic acid compounds and esterification
of 1,n-dicarbonyl compounds through the homolytic C–C bond cleavage of unstrained carbocyclic and heterocyclic ring systems. This method exhibits a lot of synthetic advantages including mild conditions, simple operation, and convenience of amplification. Mechanistic studies support the generation of peroxy radical species via oxygen capture followed by radical fragmentation.
in good yields by intramolecular hydroamination of N-alkoxy ureas in the presence of an organic photocatalyst and an inorganic base. In this reaction, the N-alkoxy urea anion generated by deprotonation undergoes photocatalyzed single-electron-transfer oxidation to generate the correspondingradical, which cyclizes to afford the imidazolinone ring. This new protocol grants access to an array of complex