enantioselective 1,3-dipolarcycloaddition of meso-diaziridines with chalcones was realized by utilizing the ScIII-N,N'-dioxide complex as the catalyst. In this transformation, the 1,3-dipole intermediates generated from the C-N bond cleavage of diaziridine were trapped by chiral N,N'-dioxide/scandium(III) complex activated chalcones to undergo enantioselective 1,3-dipolarcycloaddition. A range of chiral
CAN-mediated new, regioselective one-pot access to bicyclic cationic structures with 2,3-dihydro-1H-pyrazolo[1,2-a]pyrazol-4-ium core
作者:Mikhail I. Pleshchev、Nikita V. Das Gupta、Vladimir V. Kuznetsov、Ivan V. Fedyanin、Vadim V. Kachala、Nina N. Makhova
DOI:10.1016/j.tet.2015.09.033
日期:2015.11
[3+2]-cycloaddition of (2-bromo-2-nitrovinyl)arenes to N,N-cyclic azomethine imines, generated in situ by diaziridine ringopening in 6-Ar-1,5-diazabicyclo[3.1.0]hexanes or by metathesis of initially formed azomethine imine, followed by one-pot aromatization of the formed pyrazolidine ring.
Generation and metathesis of azomethine imines in reaction of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes with het(aryl)methylidenemalononitriles
作者:M. I. Pleshchev、V. Yu. Petukhova、V. V. Kuznetsov、D. V. Khakimov、T. S. Pivina、Yu. V. Nelyubina、N. N. Makhova
DOI:10.1007/s11172-013-0143-9
日期:2013.4
give in situ new azomethine imines inaccessible by common synthetic methods. New azomethine imines are detected as pyrazolines formed via a 1,4-H shift and trapped by the [3+2] cycloaddition with various dipolarophiles to yield 1,5-diazabicyclo[3.3.0]octanederivatives bearing pharmacophoric heterocycles, e.g. furan, nitrofuran, thiophene, and indole. The best results are achieved in the Et2O·BF3-catalyzed
Iron-catalyzed stereospecific [3+3]-annulation of aziridines with diaziridines is described to furnish [1,2,4]-triazines in high yield at room temperature. The use of an inexpensive iron salt catalyst, substrate scope and enantiomeric purity are the important practical features.
thermolysis conditions presumably occurs via the initially formed unstable dipolar bicyclic intermediates 4. Isomerization of these intermediates and subsequent addition of the second molecule of diphenylcyclopropenone with the extrusion of one molecule of carbon monoxide results in the formation of tricyclic 4a,7b-diazacyclopenta[cd]inden-7-ones 8 in good yields.
在热解条件下,由6-芳基-1,5-二氮杂双环[3.1.0]己烷1生成的偶氮甲亚胺与二甲环亚胺形成的二倍过量的二苯基环丙烯酮的正式[2 + 3]环加成反应可能是通过最初形成的不稳定的偶极双环中间体4发生的。这些中间体的异构化以及随后的第二分子二苯基环丙烯酮的加入以及一分子一氧化碳的挤出导致以良好的产率形成三环的4a,7b-二氮杂环戊[ cd ]茚满7-酮8。