Shine Henry J, Zhao Bingjun, Qian Ding-Quan, Marx John N, Guzman-Jimenez Ilse Y, Thurston John H, Ould-Ely T, Whitmire Kenton H
Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA.
J Org Chem. 2003 Nov 14;68(23):8910-7. doi: 10.1021/jo030173h.
Phenoxathiin cation radical perchlorate (PO.+ClO4(-)) added stereospecifically to cyclopentene, cyclohexene, cycloheptene, and 1,5-cyclooctadiene to give 1,2-bis(5-phenoxathiiniumyl)cycloalkane diperchlorates (4-7) in good yield. The diaxial configuration of the PO+ groups was confirmed with X-ray crystallography. Unlike additions of thianthrene cation radical perchlorate (Th.+ClO4(-)) to these cycloalkenes, no evidence for formation of monoadducts was found in the reactions of PO.+ClO4(-). This difference is discussed. Addition of Th.+ClO4(-) to five trans alkenes (2-butene, 2-pentene, 4-methyl-2-pentene, 3-octene, 5-decene) and four cis alkenes (2-pentene, 2-hexene, 2-heptene, 5-decene) gave in each case a mixture of mono- and bisadducts in which the configuration of the alkene was retained. Thus, cis alkenes gave erythro monoadducts and threo bisadducts, whereas trans alkenes gave threo monoadducts and erythro bisadducts. In these additions to alkenes, cis alkenes gave predominantly bisadducts, while trans alkenes (except for trans-2-butene) gave predominantly monoadducts. This difference is explained. 1,2-Bis(5-phenoxathiiniumyl)cycloalkanes (4-7) and 1,2-bis(5-thianthreniumyl)cycloalkanes underwent fast elimination reactions on activated alumina forming, respectively, 1-(5-phenoxathiiniumyl)cycloalkenes (8-11) and 1-(5-thianthreniumyl)cycloalkenes (12-16). Among adducts of Th.+ClO4(-) and alkenes, monoadducts underwent fast ring opening on alumina to give (5-thianthreniumyl)alkenes, while bisadducts underwent fast eliminations of H+ and thianthrene (Th) to give (5-thianthreniumyl)alkenes also. Ring opening of monoadducts was a stereospecific reaction in which the configuration of the original alkene was retained. Thus, erythro monoadducts (from cis alkenes) gave (E)-(5-thianthreniumyl)alkenes and threo monoadducts (from trans alkenes) gave (Z)-(5-thianthreniumyl)alkenes. Among bisadducts, elimination of a proton and Th occurred and was more complex, giving both (E)- and (Z)-(5-thianthreniumyl)alkenes. These results are explained. Configurations of adducts and (5-thianthreniumyl)alkenes were deduced with the aid of X-ray crystallography and (1)H and (13)C NMR spectroscopy. In the NMR spectra of (E)- and (Z)-(5-thianthreniumyl)alkenes, the alkenyl proton of Z isomers always appeared at a lower field (0.8-1.0 ppm) than that of E isomers.
将苯并噻蒽阳离子自由基高氯酸盐（PO.+ClO4(-)）立体定向地添加到环戊烯、环己烯、环庚烯和1,5 - 环辛二烯中，能以良好的产率得到1,2 - 双（5 - 苯并噻蒽鎓基）环烷二高氯酸盐（4 - 7）。通过X射线晶体学确定了PO+基团的二直立键构型。与噻蒽阳离子自由基高氯酸盐（Th.+ClO4(-)）添加到这些环烯烃中的情况不同，在PO.+ClO4(-)的反应中未发现形成单加合物的证据。对这种差异进行了讨论。将Th.+ClO4(-)添加到五种反式烯烃（2 - 丁烯、2 - 戊烯、4 - 甲基 - 2 - 戊烯、3 - 辛烯、5 - 癸烯）和四种顺式烯烃（2 - 戊烯、2 - 己烯、2 - 庚烯、5 - 癸烯）中，在每种情况下都得到单加合物和双加合物的混合物，其中烯烃的构型得以保留。因此，顺式烯烃生成赤型单加合物和苏型双加合物，而反式烯烃生成苏型单加合物和赤型双加合物。在这些与烯烃的加成反应中，顺式烯烃主要生成双加合物，而反式烯烃（除反 - 2 - 丁烯外）主要生成单加合物。对这种差异进行了解释。1,2 - 双（5 - 苯并噻蒽鎓基）环烷（4 - 7）和1,2 - 双（5 - 噻蒽鎓基）环烷在活性氧化铝上发生快速消除反应，分别生成1 - （5 - 苯并噻蒽鎓基）环烯烃（8 - 11）和1 - （5 - 噻蒽鎓基）环烯烃（12 - 16）。在Th.+ClO4(-)与烯烃的加合物中，单加合物在氧化铝上发生快速开环反应生成（5 - 噻蒽鎓基）烯烃，而双加合物也发生快速的H+和噻蒽（Th）消除反应生成（5 - 噻蒽鎓基）烯烃。单加合物的开环是一个立体定向反应，其中原始烯烃的构型得以保留。因此，赤型单加合物（来自顺式烯烃）生成（E） - （5 - 噻蒽鎓基）烯烃，苏型单加合物（来自反式烯烃）生成（Z） - （5 - 噻蒽鎓基）烯烃。在双加合物中，质子和噻蒽的消除更为复杂，生成（E） - 和（Z） - （5 - 噻蒽鎓基）烯烃。对这些结果进行了解释。借助X射线晶体学以及1H和13C NMR光谱推断了加合物和（5 - 噻蒽鎓基）烯烃的构型。在（E） - 和（Z） - （5 - 噻蒽鎓基）烯烃的NMR光谱中，Z异构体的烯基质子总是出现在比E异构体更低的场（0.8 - 1.0 ppm）。
