Oximes possessing γ-, δ-, or ω-alkenyl substituents are cyclised by N-bromosuccinimide or iodine to the corresponding cyclic nitrones or their dimeric H-bonded hydriodide salts in good yield; facially specific cycloaddition of these nitrones, and others derived by cyclisation of a δ,δ-bis(alkenyl) ketoxime or addition of acetaldoxime to cyclohexene, furnish isoxazolidines.
具有γ-、δ-或ω-烯基取代基的肟在 N-溴代琥珀酰亚胺或碘的作用下环化成相应的环状亚硝基膦或它们的二聚 H 键氢化物盐,收率很高;这些亚硝基膦以及其他通过环化δ,δ-双(烯基)酮肟或将乙醛肟加成到环己烯而得到的亚硝基膦的表面特异性环化反应生成异噁唑烷。
N-Heterocycles from Oxime and Oxime O-Benzyl Ethers via Electrophile Induced - Ring Formation. Route to Cyclic and Bicyclic Amine and Hydroxylamine
作者:H. Ali Dondas、Naciye Yaktubay
DOI:10.1515/hc.2003.9.4.337
日期:2003.1
creating cyclic and bicyclic ring systems occur in good yield. Chiral bridged-ring systems have been prepared that involve multiplication of chiral centres from one to three in one pot reactions. Formation of chiral bicyclic bridged ring N-hydroxylamine (4) and amine (7) were prepared from aldoxime (2) and oxime Ο benzyl ether (5) respectively via phenylselenyl induced cyclisations reactions. Creating bicyclo-[3
Oximes possessing γ-, δ or ω-alkenyl substituents are cyclised by phenylselenyl bromide, or by phenylselenyl chloride and an appropriate silver salt to the corresponding cyclicnitrones; the seleno nitrones undergo facially specific cycloaddition reactions with N-methylmaleimide; bis(alk-γ,δ-enyl) ketones undergo regiospecific cyclisation and stereospecific intramolecular cycloaddition to furnish spirocyclic
Bis(acetonitrile) palladium (II) chloride (10 mol %) effects cyclization of δ-alkenyl oximes to nitrones which undergo in situ 1,3-dipolar cycloaddition reactions with suitable dipolarophiles to afford a range of complex isoxazolidine derived heterocycles in high yield (81–85%).
Oximes possessing γ- or δ-alkenyl substituents are cyclised by mercuric acetate to the corresponding cyclicnitrones; the mercurated nitrones undergo facially specific cycloaddition reactions with N-methylmaleimide to afford endo- and exo-cycloadducts, δ,δ--bis(alkenyl) ketones undergo stereospecific cyclisation–intramolecular cycloaddition to furnish spirocyclic products.