Novel Synthesis of Nitrogen Heterocycles Using Zirconium-Promoted Reductive Cyclization
摘要:
Perhydroindole derivatives were prepared from enynes using zirconium-promoted reductive cyclization. The zirconacycles derived from enynes 1 were treated with iodine, isonitriles, oxygen, and carbon monoxide to give various heterocycles. The carbon-zirconium bonds of the zirconacycle could be selectively cleaved by different reagents.
A range of novel (poly)cyclic alkaloids incorporating an unprecedented 1,5-diazaspiro[2.4]heptane core that carry a spiro NH aziridine moiety and a 7-vinyl group are constructed from the thermal reaction of vinyl azides with tethered alkenes. Vinyl azides are converted to 2H-azirines in situ, which serve as enophiles for intramolecular imino-ene reactions with suitable alkenes. High stereoselectivity
Perhydroindole derivatives were prepared from enynes using zirconium-promoted reductive cyclization. The zirconacycles derived from enynes 1 were treated with iodine, isonitriles, oxygen, and carbon monoxide to give various heterocycles. The carbon-zirconium bonds of the zirconacycle could be selectively cleaved by different reagents.
The Regiochemistry of Carbenoid Insertion into Zirconacycles
作者:George J. Gordon、Tim Luker、Mark W. Tuckett、Richard J. Whitby
DOI:10.1016/s0040-4020(99)01094-7
日期:2000.4
lithium chloroallylides (allyl carbenoids) into a wide variety of unsymmetrical zirconacycles has been determined. In all but one case a single regioisomer was obtained. A combination of steric and electronic effects is needed to explain the results and imply that the carbenoid is acting predominantly as an electrophilic species. The first carbenoid insertion into a zirconacyclopentadiene is noted.