Nitrosoarenes. cycloaddition

It has been reported that the cycloaddition of arylimines with nitrosoalkenes proceeds in a 3 + 2-manner, whereas alkylimines cycloadd to nitrosoalkenes in a competitive 3 + 2- and 4 + 2-manner.80 The alkylative 3 + 2-cycloaddition of nitrosoarenes with alkynes, phenylacetylene and methyl propiolate, in the presence of K2CO3-Me2S04 produced /V-meihoxyindoles in high yields. This procedure has been used to prepare the Wasabi phytoalexins, 3-carboxy-A-alkoxyindoles.81... 

Total simple diastereoselectivity is observed in the hetero-Diels-Alder cycloaddition of nitro-soarencs to 1,3-dienes leading to the corresponding 3,6-dihydro-2//-l, 2-oxazines. A number of acyclic 1,4-disubstituted dienes have been reacted with nitrosoarenes, but the stereochemistry of the adduct 1 has not been assigned 6 s. 

The 2-aza-l, 3-butadiene (57), prepared by the action of t-butyldimethylsilyl triflate on diacetimide (MeCONHCOMe), undergoes Diels Alder cycloaddition with nitrosoarenes to yield 2-aryl-... 

The 1,2,5-oxadiazine ring-system is prepared by the addition of allylamines to nitrones (see Section 6.15.6.2.1.1), by [4-1-2] cycloaddition of 2-aza-1,3-butadienes with nitrosoarenes (see Section 6.15.6.2.2.1), and by condensation of a-haloketoximes with amidines (see Section... 

Across other double bonds Triarylketenimines react with nitrosoarenes via a [2-1-2] cycloaddition reaction across the N=0 bond to give the four-membered ring cycloadduct 64 Some cycloadducts are only stable in solution and they rapidly undergo a cycloreversion reaction to form diphenylcarbodiimide and diphenylketone. 

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