1,3‐Alkyl Transposition in Allylic Alcohols Enabled by Proton‐Coupled Electron Transfer
作者:Kuo Zhao、Gesa Seidler、Robert R. Knowles
DOI:10.1002/anie.202105285
日期:2021.9.6
for the isomerization of acyclic allylic alcohols into β-functionalized ketones via 1,3-alkyl transposition. This reaction proceeds via light-driven proton-coupled electron transfer (PCET) activation of the O−H bond in the allylic alcohol substrate, followed by C−C β-scission of the resulting alkoxy radical. The transient alkyl radical and enone acceptor generated in the scission event subsequently
feasibility and inherent benefits of combining two distinct asymmetric transition-metal-catalyzed reactions in one pot. The reported transformation features a Pd-catalyzed asymmetricallylicalkylation and a Rh-catalyzed enantioselective 1,4-conjugate addition, effectively converting simple allyl enol carbonate precursors into enantioenrichedcyclic ketones with two remote stereocenters. Despite the anticipated
An unprecedented photoinduced azide–alkene cycloaddition has been developed, the key elements of which include the photoisomerization of cis-cycloheptenone to trans-cycloheptenone, strain-promoted 1,3-dipolar cycloaddition of trans-cycloheptenone with azide, and aerobic oxidative aromatization of the resulting 1,2,3-triazoline. The newly developed photoclick reactions display several appealing features
Tuning the Reactivity of Ketones through Unsaturation: Construction of Cyclic and Acyclic Quaternary Stereocenters via Zn-ProPhenol Catalyzed Mannich Reactions
作者:Barry M. Trost、Chao-I Joey Hung、Elumalai Gnanamani
DOI:10.1021/acscatal.8b04685
日期:2019.2.1
Zn-ProPhenol catalyzed Mannich reactions between N-carbamoyl imines and a-branched ketones. Despite only a small change in the substrate acidity, the bimetallic catalyst can preferentially recognize and activate unsaturated ketones over their fully saturated counterparts, providing a chemo-, diastereo-, and enantioselective route to valuable β-aminoketones bearing both cyclic and acyclic quaternary stereocenters
A short conversion of cyclohexanones to cycloheptenones
作者:Shangjin Yang、Benno Hungerhoff、Peter Metz
DOI:10.1016/s0040-4039(98)00298-6
日期:1998.4
Cycloheptenones are efficiently prepared from cyclohexanones via organoaluminum-promoted ringenlargement with trimethylsilydiazomethane and subsequent palladium(II)-catalyzed dehydrosilylation.