シリカゲル担持硫酸塩を触媒とする選択的反応およびシリカゲル担持硝酸塩を用いた酸化反応
固体表面での有機合成
1993 年 51 巻 4 号 p. 308-316
詳細
1993 年 51 巻 4 号 p. 308-316
Metallic sulfates supported on silica gel efficiently catalyze dehydration and transesterification of alcohols. Symmetrical primary and secondary diols from C2 to C16 have been monoprotected in high selectivity by acylation and THP-ether formation by these catalysts in ester/alkane and DHP/alkane mixtures, respectively. The selectivity of these reactions depends upon the composition and the volume of the solvent systems. The selectivity can be explained by (1) preferential adsorption of diols to monoesters or monoethers and (2) the formation of thin liquid films of diols on the surface of the catalysts caused by the limited dissolution of the diols in the solvents. Metallic nitrates supported on silica gel efficiently oxidized secondary and primary benzyl and allyl alcohols and ethers to the corresponding ketones and aldehydes under mild conditions. Silica gel is essential for the efficient oxidation and Cu (NO3)2 and Zn (NO3)2 are suitable for practical use. Mechanistic study suggests that NO2 is an active species. Alcohols and ethers are readily oxidized by NO2 to give the corresponding aldehydes or ketones in the presence of silica gel.
