Azoxides, cycloaddition

C-NMR analysis revealed signals at 6= 142.5 and 135.7 ppm due to C7a and C3a respectively, and molecular ion m/z = 386 was observed as the base peak in the mass spectrum. Although formation of oxadiazolines is possible in principle by the [3+2] cycloaddition of azoxides and alkenes, they are predicted to be unstable with the likely mode of decomposition being the retro 1,3-dipolar addition to the azoxide and alkene (Section 5.03.2). 

The addition of ZnBi 2 to die tandem 1,3-azaprotio cyclotransfer-cycloaddition of a ketoxime with divinyl ketone results in rate enhancement and the exclusive formation of l-aza-7-oxabicyclo[3.2.1]octan-3-ones.79 The 1,3-dipolar cycloaddition of 1-aza-l-cyclooctene 1-oxide with alkenes produces the corresponding isoxazolidines in high yields with a minimum of polymeric material.80 The cycloaddition of thiophene-2 -carbaldehyde oxime with acetonitrile and methyl acrylate produces the 1,3-dipolar adduct, substituted isoxazolidines, and not the previously reported 4 + 2-adducts.81 Density functional theory and semi-empirical methods have been used to investigate the 3 + 2-cycloaddition of azoxides with alkenes to produce 1,2,3-oxadiazolidines.82 The 3 + 2-cycloaddition of a-nitrosostyrenes (62) with 1,3-diazabuta-l,3-dienes (63) and imines produces functionalized cyclic nitrones (64) regioselectively (Scheme 22).83... 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ , ]

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