Practical Iron-Catalyzed Allylations of Aryl Grignard Reagents
作者:Matthias Mayer、Waldemar M. Czaplik、Axel Jacobi von Wangelin
DOI:10.1002/adsc.201000228
日期:2010.9.10
reaction between aryl halides and allyl electrophiles has been developed. The underlying domino process exhibits high versatility with respect to the allylic leaving group (acetate, tosylate, diethyl phosphate, methyl carbonate, trimethylsilanolate, methanethiolate, chloride, bromide) and high economic and environmental sustainability with respect to the catalyst system (0.2–5 mol% tris(acetylacetonato)iron(III)
The coupling of arylboronicacids with electron-rich allylicbromides is accomplished in the absence of any transition-metal catalyst through conventional heating. The reaction is completely regioselective, affording only the α-coupled product, and can be carried out under mild aerobic conditions in an organic solvent; the presence of a base is required.
Tertiary, benzyl, and allylic nitro compounds undergo nuclephilic substitutionreactions with carbonnucleophiles such as electron rich aromatic compounds, allylsilanes, or silyl enol ethers in the presence of SnCl4.
An efficient dehydrogenative Diels–Alderreaction of prenyl derivatives with dienophiles has been developed. The reaction exhibits broad substrate scope and provides efficient access to cyclohexene derivatives with good to excellent yields. A reasonable mechanism involving a metal-free thermal reversible process is proposed.
A metal‐free dehydrogenative Diels‐Alderreaction of substituted alkenes for the synthesis of tetrahydroisoindolinones has been exploited for the first time. This new method features functional group tolerance and broad substrate scope, providing an efficient access to biologically active tetrahydroisoindolinone skeletons with endo steroselectivity in good to excellent yields.