Department of Chemistry, Kanagawa University, Tsuchiya, Hiratsuka, Kanagawa 259-1293, Japan.
J Org Chem. 2010 Feb 5;75(3):879-84. doi: 10.1021/jo902477n.
The singlet oxygenation of 4-tert-butyl-3,3-dimethyl-5-(3-oxyphenyl)-2,3-dihydrothiophenes 5c-e bearing an acetoxy or methoxy group at the 2-position exclusively gave the corresponding sulfanyl-substituted bicyclic dioxetanes 2c-e, while that of 5a without 2-substituent mainly gave sulfoxide 11 along with a small amount of dioxetane 2a. These dioxetanes were sufficiently stable thermally to permit handling at room temperature. Sulfanyl-substituted dioxetanes, 2c and 2e, were further oxidized with m-chloroperbenzoic acid to afford the corresponding sulfinyl-substituted dioxetanes 3c, 3e and sulfonyl-substituted dioxetanes 4c, 4e. X-ray single crystallographic analysis was performed for 2c and 4e. Base-induced decomposition of the dioxetanes in DMSO gave light with a maximum wavelength lambda(max)(CL) at 554 nm for 2a and 565 nm for 2e in moderate light yields, while sulfinyl-derivative 3e gave weak light with lambda(max)(CL) = 795 nm and sulfonyl-derivative 4e gave very weak light with lambda(max)(CL) = 848 nm.
4-叔丁基-3,3-二甲基-5-(3-氧代苯基)-2,3-二氢噻吩 5c-e 在 2-位带有乙酰氧基或甲氧基，单重态氧的氧合作用仅生成相应的硫杂双环二氧戊环 2c-e，而没有 2-取代基的 5a 主要生成亚砜 11 以及少量的二氧戊环 2a。这些二氧戊环在热稳定性方面足够稳定，可以在室温下处理。硫杂双环二氧戊环 2c 和 2e 进一步用间氯过苯甲酸氧化，得到相应的亚磺酰基取代的二氧戊环 3c、3e 和磺酰基取代的二氧戊环 4c、4e。对 2c 和 4e 进行了 X 射线单晶结构分析。二氧戊环在 DMSO 中的碱性分解产生了光，对于 2a，最大波长 lambda(max)(CL)为 554nm，对于 2e，为 565nm，光产率适中，而亚磺酰基衍生物 3e 产生弱光，最大波长 lambda(max)(CL)为 795nm，磺酰基衍生物 4e 产生非常弱的光，最大波长 lambda(max)(CL)为 848nm。
