- Dichloromethane activation. Direct methylenation of ketones and aldehydes with CH2Cl2 promoted by Mg/TiCl4/THF
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(Chemical Equation Presented) This Mg-TiCl4-promoted CH 2-transfer reaction of CH2Cl2 represents an extremely simple, practical, and efficient methylenation of a variety of ketones and aldehydes, especially in enolizable or sterically hindered ketones such as 2,2-dimethylcyclohexanone, camphor, and fenchone.
- Yan, Tu-Hsin,Tsai, Chia-Chung,Chien, Ching-Ting,Cho, Chia-Ching,Huang, Pei-Chen
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p. 4961 - 4963
(2007/10/03)
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- Ketone methylenation using the Tebbe and Wittig reagents - A comparison
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Ketone methylenation has been accomplished using the Tebbe and the Wittig reagents. Comparison of the two reagents for a variety of ketones shows that the Tebbe reagent gives better product yields than the Wittig reagent. This is particularly important when the ketone substrate is hindered. It is also noted that the Tebbe reaction accomplishes methylenation in a non-basic medium, thus racemization does not take place on substrates with enolizable chiral centers.
- Pine,Shen,Hoang
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p. 165 - 167
(2007/10/02)
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- THE METHYLENATION OF ENOLIZABLE KETONES AND ESTERS USING ORGANOTITANIUM CHEMISTRY
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The titanium methylidene fragment, Cp2Ti=CH2, resulting from Tebbe's reagent, Cp2TiCH2*AlMe2Cl or the β,β-disubstituted metallacycle, Cp2TiCH2C(Me)(n-Pr)CH2, methylenates enolizable acidic ketones and converts α,α-disubstituted ketones into titanium enolates.The reagent reacts selectively with ketones over esters.
- Clawson, Leigh,Buchwald, Stephen L.,Grubbs, Robert H.
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p. 5733 - 5736
(2007/10/02)
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