Synthetic Studies in the Intramolecular Carbocyclization of <i>N</i>-Acyloxyiminium Ions. Stereoelectronic and Steric Implications of Nucleophilic Alkene, Alkyne, and Allene Tethers
作者:Stephen Hanessian、Martin Tremblay、Mauro Marzi、Juan R. Del Valle
DOI:10.1021/jo050326w
日期:2005.6.1
acid mediated carbocyclization to give stereodefined azacyclic compounds depending on the nature of the nucleophilic tether. In general, reactions of alkenes and alkynes with terminal alkyl or aryl substituents, as well as allenes, proceed through transient vinylic carbocations that are attacked internally by the N-Boc group to give tricyclic dihydrooxazinones. Diastereotopic bis-4-(3-butenyl) and 4-(3-butynyl)
由带有4-(3-丁烯基),4-(3-丁炔基),4-(3-肉桂基甲基)和4-烯丙基系链的4-取代的1-焦谷氨酸酯生成的N-酰氧基亚胺离子经历快速Lewis酸介导的碳环化反应根据亲核系链的性质,得到立体定义的氮杂环化合物。通常,烯烃和炔烃与末端烷基或芳基取代基以及丙二烯的反应会通过被N内部侵蚀的瞬时乙烯基碳阳离子进行-Boc基团给出三环二氢恶嗪酮。非对位双-4--4-(3-丁烯基)和4-(3-丁炔基)系链受到立体化学控制的攻击,倾向于采用反平面而不是向斜取向的方法生成对映体纯的6-卤代八氢吲哚-2-羧酸和6-卤代六氢吲哚-2-羧酸分别作为它们的甲酯。氮杂双环和三环化合物是出色的多样化支架。