Microwave-Assisted Syntheses of <i>N</i>-Heterocycles Using Alkenone-, Alkynone- and Aryl-carbonyl <i>O</i>-Phenyl Oximes: Formal Synthesis of Neocryptolepine
作者:Fernando Portela-Cubillo、Jackie S. Scott、John C. Walton
DOI:10.1021/jo800847h
日期:2008.7.1
approach enabled the natural product trisphaeridine to be made. Starting from 2-phenylnicotinaldehyde derivatives, ring closures of the derived iminyl radicals onto the phenyl rings yielded benzo[h][1,6]naphthyridines. Similarly, ring closure onto a phenyl ring from a benzothiophene-based iminyl yielded a benzo[b]thieno[2,3-c]quinoline. By way of contrast, iminyl radical ring closure onto pyridine rings was
这项研究旨在提供一种新的“清洁”的合成方法,该方法将能够有效地制备已知和新颖的N-杂环。发现O-苯基肟是具有各种受体侧链的亚氨基自由基的优异前体。由含有戊-4-烯受体的O-苯基肟以高收率制得双羟基吡咯。使用六-5-烯基受体的类似过程未产生二氢吡啶,可能是因为6- exo - trig亚胺基的闭环太慢,无法与H原子抽象竞争。来自具有戊-4-炔型侧链的前体的亚胺基进行闭环,然后重排以提供吡咯衍生物。合适地取代的亚氨基自由基容易地闭环在芳族受体上,因此使得能够使用多个多环系统。喹啉由3-苯基丙烷经O-苯基肟制得。由2-甲酰基联苯开始的菲啶的合成特别有效,这种方法可以制备天然产物三菲啶。从2-苯基烟碱醛衍生物开始,衍生的亚氨基自由基在苯环上的闭环产生苯并[ h]] [1,6]萘啶。类似地,将苯并噻吩基亚胺基的苯环闭环,得到苯并[ b ]噻吩并[2,3- c ]喹啉。相比之下,未观察到亚吡啶基自由基
Dioxime oxalates; new iminyl radical precursors for syntheses of N-heterocycles
作者:Fernando Portela-Cubillo、James Lymer、Eoin M. Scanlan、Jackie S. Scott、John C. Walton
DOI:10.1016/j.tet.2008.08.112
日期:2008.12
an atom-efficient way of generating iminylradicals. The process was most efficient for dioxime oxalates having aryl substituents attached to their CN bonds. The method was useful for EPR spectroscopic study of iminyl and iminoxyl radicals. Photolyses in toluene solution, of dioxime oxalates containing alkenyl acceptor groups, yielded unsaturated iminylradicals that ring closed to afford 3,4-dihydro-2H-pyrroles
From dioxime oxalates to dihydropyrroles and phenanthridines via iminyl radicals
作者:Fernando Portela-Cubillo、Eoin M. Scanlan、Jackie S. Scott、John C. Walton
DOI:10.1039/b808625g
日期:——
Dioxime oxalates are useful precursors for the clean generation of iminyl radicals by sensitised UV photolysis and can be adapted for serviceable preparations of 3,4-dihydro-2H-pyrroles and phenanthridines.
Microwave-assisted preparations of dihydropyrroles from alkenone O-phenyl oximes
作者:Fernando Portela-Cubillo、Jackie S. Scott、John C. Walton
DOI:10.1039/b712582h
日期:——
Microwave irradiation of alkenone O-phenyl oximes produces iminyl radicals that ring close to yield dihydropyrrole derivatives; pyrroles and pyridines can be obtained from related precursors.
烯酮O-苯基肟的微波辐射产生亚胺基,其环附近产生二氢吡咯衍生物。吡咯和吡啶可从相关的前体获得。
Thermal Rearrangement of Indolyl Oxime Esters to Pyridoindoles
作者:Fernando Portela-Cubillo、Brian A. Surgenor、R. Alan Aitken、John C. Walton
DOI:10.1021/jo801751a
日期:2008.10.17
Acyl oximes derived from a variety of indolylalkanones underwent a ring closure sequence during FVP to afford 9H-pyrido[2,3-b]indoles. Unlike UV light promoted reactions of oxime esters, the mechanism is almost certainly not mediated by iminyl radicals but probably involves tautomerism, elimination of acetic acid, and a final electrocyclic ring closure.