- Catalytic Allylic Oxidation of Cyclic Enamides and 3,4-Dihydro-2H-Pyrans by TBHP
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Allylic oxidation of heteroatom substituted cyclic alkenes by tert-butyl hydroperoxide (70% TBHP in water) using catalytic dirhodium caprolactamate [Rh2(cap)4] forms enone products with a variety of 2-substituted cyclic enamides and 3,4-dihyro-2H-pyrans. These reactions occur under mild reaction conditions, are operationally convenient to execute, and are effective for product formation with as low as 0.25 mol% catalyst loading. With heteroatom stabilization of the intermediate allylic free radical two sites for oxidative product formation are possible, and the selectivity of the oxidative process varies with the heteroatom when R = H. Cyclic enamides produce 4-piperidones in good yields when R = alkyl or aryl, but oxidation of 2H-pyrans also gives alkyl cleavage products. Alternative catalysts for TBHP oxidations show comparable selectivities but give lower product yields.
- Yu, Yang,Humeidi, Ranad,Alleyn, James R.,Doyle, Michael P.
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p. 8506 - 8513
(2017/08/23)
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- Tandem cross enyne metathesis (CEYM)-intramolecular Diels-Alder reaction (IMDAR). An easy entry to linear bicyclic scaffolds
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A new tandem cross enyne metathesis (CEYM)-intramolecular Diels-Alder reaction (IMDAR) has been carried out. It involves conjugated ketones, esters or amides bearing a remote olefin and aromatic alkynes as the starting materials. The overall process enabl
- Miró, Javier,Sánchez-Roselló, María,Sanz, álvaro,Rabasa, Fernando,Del Pozo, Carlos,Fustero, Santos
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supporting information
p. 1486 - 1493
(2016/04/09)
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