Oximes, azido synthesis

N, C -Coupling reaction of BENA with trimethylsilyl azide is the key step of a very convenient and versatile procedure for the synthesis of otherwise difficultly accessible a-azido oximes (524, 525) (Scheme 3.248). 

Due to these procedures as well as to some other transformations, the a-azido oximes can be considered as efficient basic reagents in the synthesis of various derivatives of 1,2-disubstituted ethanes using readily available AN (431) as starting compounds. 

The [Ru(bpy)3] photocatalyst was also applied in the following novel visible-light driven processes (i) synthesis of indazolo[2,3-a]quinoline derivatives from 2-(2-nitrophenyl)-l,2,3,4-tetra-hydroquinolines (ii) azido- and amino-trifluoromethylation of alkenes (iii) reduction of nitro compounds to oximes (iv) generation of aryl radicals by visible-light photocatalytic reduction of sulfonium salts. ... 

Benzisoxazoles.—The reaction of salicylaldehyde oxime with thionyl chloride in pyridine to yield 1,2-benzisoxazole (539 R = H) constitutes a new synthesis of this ring system.Thermolysis of the azido-ketone (540) affords the linearly annelated anthranil (541). ° The benzisoxazoles (539 R = H, Me, or Ph) rearrange photochemically to the benzoxazoles (543) via intermediate azirines (542). ° Irradiation of an aqueous solution of the benzisoxazolium salt (544) gives the phenolic ketone (545). ° ... 

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