Stereoselective and Stereospecific Reactions. III. Benzoylation, Cyclfzation, and Epimerization of Diols
作者:Oyo Mitsunobu、Junji Kimura、Ken-ichi Iiizumi、Noboru Yanagida
DOI:10.1246/bcsj.49.510
日期:1976.2
The benzoylation of various classes of diols by means of diethyl azodicarboxylate (1) and triphenylphosphine (2) was carried out at room temperature. When primary–secondary diols were treated with an equimolar amount of benzoic acid (3) in the presence of 1.5 molar equivalents of 1 and 2, reaction mainly Occurred at their primary hydroxyl functions. Secondary–secondary diols gave mono- and dibenzoylated products or cyclic ethers. The course of the reactions depends on the structure of diols used. Thus, intermolecular displacement giving benzoates is a favorable process for 1,3-butanediol, 2,4-pentanediol and trans-1,2-indanediol, while 2,5-hexanediol and trans-1,2-cyclohexanediol afford the cyclized products.
各种类二醇的苯甲酰化反应通过二乙基偶氮二羧酸酯(1)和三苯基膦(2)在室温下进行。当初级-次级二醇与等摩尔的苯甲酸(3)在1和2的1.5摩尔当量存在下反应时,反应主要发生在它们的初级羟基功能上。次级-次级二醇则产生单苯甲酸酯、双苯甲酸酯或环醚。反应的进程依赖于所使用二醇的结构。因此,对于1,3-丁二醇、2,4-戊二醇和反-1,2-茚二醇,给出苯甲酸酯的分子间取代反应是有利的,而2,5-己二醇和反-1,2-环己二醇则产生环化产物。