- Practical and Safe Sulfonylation of 2-Alkynyl and 2-Alkenyl Alcohols Using the Combined Bases of a Catalytic Amount of Tertiary Amine and Potassium Carbonate
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Several 2-alkynyl and 2-alkenyl alcohols were effectively sulfonylated with methanesulfonyl chloride or p-toluenesulfonyl chloride using the combined bases of a catalytic amount of tertiary amine and potassium carbonate.The reaction was conducted with reliable safety and while avoiding the disposal of wasted amines.The mesylation of 2-propyn-1-ol proceeded on a large scale (more than 20 kg) without a substantial production of explosive 3-chloro-1-propyne.The choice of the catalysts was important, and sterically unhindered tertiary amines, such as trimethylamine, N,N-d imethylbenzylamine, and triethylamine, were effective.Without these catalysts the reactions were significantly retarded.The reaction was so mild that it could be applied to complex and optically active 4-hydroxy-3-methyl-2-(2-propynyl)-2-cyclopenten-1-one, which is an important alcohol moiety of synthetic pyrethroids.
- Tanabe, Yoo,Yamamoto, Hitomi,Yoshida, Yoshihiro,Miyawaki, Takashi,Utsumi, Naoka
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p. 297 - 300
(2007/10/02)
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- Preparation of (4S)-4-hydroxy-3-methyl-2-(2′-propynyl)-2-cyclopentenone by combination of enzymatic hydrolysis and chemical transformation
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(4S)-4-Hydroxy-3-methyl-2-(2′-propynyl)-2-cyclopentenone ((S)-2), which is an important alcohol moiety of optically active pyrethroid insecticides, was prepared from the corresponding racemic acetate ((±)-1) by the combination of enzymatic hydrolysis and chemical transformation in high chemical and optical yields.
- Danda, Hidenori,Maehara, Akira,Umemura, Takeaki
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p. 5119 - 5122
(2007/10/02)
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- PREPARATION OF OPTICALLY ACTIVE SECONDARY ALCOHOLS BY COMBINATION OF ENZYMATIC HYDROLYSIS AND CHEMICAL TRANSFORMATION
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Several kinds of optically active secondary alcohols (S)-2, which are important intermediates of bioactive compounds, were prepared from the corresponding racemic acetate (+/-)-1 in high chemical and optical yields by combination of enzymatic hydrolysis and chemical transformation.
- Danda, Hidenori,Nagatomi, Toshio,Maehara, Akira,Umemura, Takeaki
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p. 8701 - 8716
(2007/10/02)
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- Process for producing optically active cyclopentenolones
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Optically active cyclopentenolones, which are useful as an intermediate of pyrethroid insecticides, are produced from racemic cyclopentenolones according to the following procedures; (1) asymmetric hydrolysis of racemic carboxylate esters of the cyclopentenolones, (2) nitrate- or sulfonate-esterification of the asymmetrical hydrolysis products, and (3) hydrolysis of the esterification products.
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