Heterocyclizations Based on SNH Reactions

All heterocyclizations based on SnH reactions can be conveniently divided into 

Cyclizations of this kind are, perhaps, the most numerous. They may proceed either by the conventional SN2Ar pathway (oxidative or non-oxidative) or through one of the above-mentioned non-conventional mechanisms. The term one-step means of course that all possible precursors of substrate as well as non-isolable intermediates are not taken into consideration. 

H Ph 4-MeC6H4 4-ClC6H4 4-BrC6H4 PhNHNH2, AcOH, aq. HC1, reflux, 5-10 h a 57AG479 66ZC329 86IJC(B)901 

H H Me CH2Ph 02, EtOH, aq. H2S04, reflux, 4h 75-80 02MC68 03RCB2175 

Me PhCO 2-ClC6H4CO 4-ClC6H4CO Chloroanil, xylene, reflux, 12 h 35-48 01JHC829 

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