Synthesis and isomerization of the novel heterotriptycene, 8-hydroxy-2,4,5′,6-tetramethyl-4,8-dihydro-4,8[3′,2′]thiophenobenzo[1,2-b : 5,4-b′]dithiophene
Synthesis and isomerization of the novel heterotriptycene, 8-hydroxy-2,4,5′,6-tetramethyl-4,8-dihydro-4,8[3′,2′]thiophenobenzo[1,2-b : 5,4-b′]dithiophene
The reaction of 1,1,1-tris(2-lithio-5-methyl-3-thienyl)ethane with diethyl carbonate yields the novel heterotriptycene 2, which isomerizes to ketone 7 either by heating or under acidic or basic conditions.
1-tris(3-bromo-5-methyl-2-thienyl)ethane 40, with dimethyl carbonate. Attempts to prepare 8-hydroxy-4-tert-butyl- 31 and 8-hydroxy-4-unsubstituted thiophenetriptycenes resulted in the formation of ketone 29 and hydroperoxide 32, respectively. The 8-hydroxy-4-methylthiophenetriptycene 1 decomposed to the corresponding ketone 26 on heating. Attempts to generate the carbocation at the bridgehead of compound 1 by dissolution
通过用碳酸二乙酯处理由1,1,1-三(2-溴-4-甲基-3-噻吩基)乙烷13制得的三锂盐来合成8-羟基-4-甲基噻吩并三苯并噻吩1。以类似的方式,制备了8-羟基-4-乙基噻吩三烯27。还通过使衍生自1,1,1-三(3-溴-5-甲基-2-甲基噻吩基)乙烷40的三锂盐与碳酸二甲酯反应获得4-羟基-8-甲基异构体11。尝试制备8-羟基-4-叔叔-丁基-31和8-羟基-4-未取代的噻吩三萜分别导致酮29和氢过氧化物32的形成。8-羟基-4-甲基噻吩三茂烯1在加热时分解成相应的酮26。试图通过浓溶液中的溶解在化合物1的桥头处生成碳正离子化。H 2 SO 4或通过乙磺酸的乙酰化作用均未成功。化合物1的8-乙酰氧基(45)和8-甲氧基(46)衍生物是通过在DMAP存在下用乙酸酐在三乙胺中处理化合物1和分别用四氟硼酸三甲基氧鎓甲基化化合物1的锂盐来制备的。区域异构体1和11的红外光谱比较表明,化合物1中桥
Photoirradiation of 4,8-dihydro-4,8[3′,2′]thiophenobenzo[1,2-b:5,4-b′]dithiophenes (thiophenetriptycenes) results in di-π-methane rearrangement to provide the corresponding semibullvalenes. In the initial stage of the di-π-methane rearrangement, C(7a)-C(8a) bridging occurs exclusively regardless of bridgehead substituents.