THE EFFICIENCY OF BENZIL-SENSITIZED PHOTOEPOXIDATION - A CORRECTION
THE EFFICIENCY OF BENZIL-SENSITIZED PHOTOEPOXIDATION - A CORRECTION
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DOI：
10.1021/ja00375a031
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发表时间：
1982-01-01
影响因子：
15
通讯作者：
SHIMIZU, N
中科院分区：
文献类型：
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作者：
BARTLETT, PD;ROOF, AAM;SHIMIZU, N
苯偶酰光敏化环氧化异戊烯导致每消耗一个二酮分子约两个或更少的环氧化物分子，而不是先前报道的更大的数字。在α-二酮对烯烃的光环氧化反应的原始报告中，对主要与联乙酰和苯偶酰反应的一些烯烃进行了调查，比较了产率和敏化剂效率。而双乙酰敏化的环氧化反应总是需要1摩尔的双乙酰，以产生高达2摩尔的环氧化物，更高的回收率的苯偶酰报道，表明环氧化效率高达16摩尔的环氧化物每摩尔的苯偶酰消耗。在跟踪这些物质平衡对反应机理的影响的过程中，我们发现苯偶酰光敏化的分析方法中存在严重错误，
Photosensitized epoxidation of norbornene by benzil leads to about two epoxide molecules or less per diketone molecule consumed, not the larger numbers previously reported. 3 It is not necessary to postulate a chain mechanism for this epoxidation, although side reactions still complicatethe process in many cases.In the original report3 of photoepoxidation of olefins by a-diketones, a survey was made of a number of olefins in reaction chiefly with biacetyl and benzil, comparing the yields and sensitizer efficiencies. Whereas the biacetyl-sensitized epoxidation always required 1 mol of biacetyl to produce up to 2 mol of epoxide, much higher recoveries of benzil were reported, indicating epoxidation efficiencies upto 16 mol of epoxide per mol of benzil consumed. In the course of following up the implications of these material balances for the reaction mechanism, we have found a serious error in the analytical procedure for the benzil photosensitizations,