Intramolecular Reaction of a Phenonium Ion. Novel Lactonization of 4-Aryl-5-tosyloxypentanoates and 4-Aryl-5-tosyloxyhexanoates Concomitant with a Phenyl Rearrangement<sup>1</sup>
作者:Shinji Nagumo、Machiko Ono、Yo-ichiro Kakimoto、Tsuneo Furukawa、Tomoaki Hisano、Megumi Mizukami、Norio Kawahara、Hiroyuki Akita
DOI:10.1021/jo010500q
日期:2002.9.1
of the aromatic ring on the reactivity, it was found that the reaction proceeded via a phenonium ion. This finding was supported by the stereochemical results for the lactonization of optical active 1. Silica gel-promoted lactonization of 1 gave only gamma-lactone 2, whereas that of 3 afforded gamma-lactone 4 and delta-lactone 5. These lactonizations proved to be kinetically controlled. On the other
报道了4-芳基-5-甲苯磺酰氧基戊酸甲酯1和4-芳基-5-甲苯磺酰氧基己酸酯3伴随苯基重排的新型内酯化。通过硅胶或在各种溶剂中加热促进内酯化。通过检查芳环的取代基对反应性的影响,发现反应通过a离子进行。光学活性物质1的内酯化的立体化学结果支持了这一发现。硅胶促进的内酯化1仅产生γ-内酯2,而硅胶3的内酯化产生γ-内酯4和δ-内酯5。这些内酯化被证明是动力学控制的。另一方面,当将3c在CH(3)NO(2)中于70℃加热时,观察到4c的高选择性形成。