- Stereospecific Electrophilic Fluorocyclization of α,β-Unsaturated Amides with Selectfluor
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An efficient fluorocyclization of α,β-unsaturated amides through a formal halocyclization process is developed. The reaction proceeds under transition-metal-free conditions and leads to the formation of fluorinated oxazolidine-2,4-diones with excellent regio- and diastereoselectivity. The evaluation of the reaction mechanism based on preliminary experiments and density functional theory calculations suggests that a synergetic syn-oxo-fluorination occurs and is followed by an anti-oxo substitution reaction. The reaction opens a new window in the field of stereospecific fluorofunctionalization.
- Fei, Haiyang,Fu, Yao,Jalani, Hitesh B.,Li, Guigen,Lu, Hongjian,Wu, Hongmiao,Xu, Zheyuan,Zhu, Lin
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supporting information
(2020/03/30)
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- Synthesis of β-, γ-, and δ-lactams via Pd(II)-catalyzed C-H activation reactions
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Pd(II)-catalyzed intramolecular amination of sp2 and sp3 C-H bonds are developed using a combination of CuCl2 and AgOAc as the oxidant. The reaction protocol tolerates the presence of a double bond in the substrates. This catalytic reaction provides practical access to a wide range of β-, γ-, and δ-lactams. Copyright
- Wasa, Masayuki,Yu, Jin-Quan
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supporting information; experimental part
p. 14058 - 14059
(2009/03/11)
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- Kinetics and Mechanism of the Ivanov Reaction: Reaction of Aldehydes and Ketones with Phenylacetic Acit Magnesium Enediolate
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Stopped-flow kinetics of the reaction between aldehydes or ketones and the magnesium enediolate of phenylacetic acid in THF are second order at enediolate concentrations -3 M.At concentrations of 10-3 - 3*10-2 M, the formation of a bis(enediolate) requires a more complex kinetic equation.Second-order rate constans are reported for the reaction of the enediolate with a number of aldehydes and ketones at 25 deg C.Entropies of activation for cyclohexanone, benzaldehyde, 2-methylpropanal, and 2,2-dimethylpropanal are positive, and enthalpy-entropy compensation is observed.Ef fects of cycloalkanone ring size and benzaldehyde substituents are small and are ascribable to a transition state with a very small C-C bond order.A two-step mechanism is proposed, with preequilibrium formation of a coordination intermediate which, in some cases, is accompanied by a change in the magnesium coordination number.Effects of alkyl groups on aldehyde and ketone reactivity stem mainly from steric desolvation.
- Toullec, Jean,Mladenova, Margarita,Gaudemar-Bardone, Francoise,Blagoev, Blagoi
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p. 2563 - 2569
(2007/10/02)
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