Reactions of diethyl azulene-1,3-dicarboxylate derivatives and 1-azaazulene derivatives with Grignard reagents, and alkyl- and aryllithium
作者:Tadayoshi Morita、Noritaka Abe、Kahei Takase
DOI:10.1039/b003078n
日期:——
Reactions of diethyl azulene-1,3-dicarboxylate (1) and diethyl 2-chloroazulene-1,3-dicarboxylate (11) with Grignard reagents, followed by dehydration with tetrachloro-1,2-benzoquinone, gave 2-, 4,- and 6-substituted addition–oxidation products. Grignards reagents have a tendency to react with 1 at the positions in the order of 2 > 4 > 6, while steric hindrance has a greater influence at the positions in order of 2 > 4 > 6. Reactions of 1 and 11 with phenyllithium and methyllithium gave similar results. On the other hand, on the reaction of diethyl 2-methoxyazulene-1,3-dicarboxylate (15), Grignard reagents attacked preferentially at the methoxy group, and 2-substituted products were obtained. Use of excess molar equivalents of Grignard reagents led to diaryl-substituted products. Reaction of 2-chloro-1-azaazulenes with Grignard reagents also gave similar addition–oxidation products, and reacted at the positions in the order 8 ≫ 4 > 6, whereas reaction of 2-methoxy-1-azaazulene with a Grignard reagent gave 1-azaazulen-2(1H)-one.
二乙基azulene-1,3-二羧酸酯(1)和二乙基2-氯azulene-1,3-二羧酸酯(11)与格氏试剂反应,随后与四氯-1,2-苯并醌脱水,生成了2-、4-和6-取代的加成-氧化产物。格氏试剂倾向于按照2 > 4 > 6的顺序与1反应,而立体位阻在2 > 4 > 6的位置上有更大的影响。1和11与苯基锂和甲基锂的反应结果相似。另一方面,二乙基2-甲氧基azulene-1,3-二羧酸酯(15)的反应中,格氏试剂优先攻击甲氧基,得到2-取代产物。使用过量的格氏试剂会导致二芳基取代产物的形成。2-氯-1-氮杂azulenes与格氏试剂的反应也生成类似的加成-氧化产物,反应位置的顺序为8 ≫ 4 > 6,而2-甲氧基-1-氮杂azulene与格氏试剂的反应则生成1-氮杂azulen-2(1H)-酮。