1‐(Azidomethyl)benzotriazole reacts with alkynes to give mixtures of isomeric 1,2,3‐triazoles, whereas the interactions of 1‐(azidomethyl)benzotriazole and ‐5‐phenyl‐1,2,3,4‐tetrazole with alkenes proceed regioselectively to form 1,2,3‐triazolines and/or aziridines and enamines in good yields. Diheterocyclosubstituted methanes thus obtained were investigated with respect to thermolysis, α‐lithiation, and reactions with Grignard reagents.
1‐(2‐Chloropropen‐2‐yl)benzotriazole (6) is converted by heating with sodium hydroxide or by lithium diisopropylamide at ‐78° into 1‐allenylbenzotriazole (1) in high yield. Allene 1 undergoes in situ lithiation at the α‐carbon and subsequent reactions with iodomethane or carbonyl compounds to produce 1‐(1‐substituted allenyl)benzotriazoles 9 and 2a‐c, respectively. Three equivalents of lithium diisopropylamide dilithiated 1 and afforded symmetrical 1‐(1,3‐disubstituted allenyl)benzotriazoles 11a,b upon reaction with ketones. The unsymmetrical 1‐(1,3‐disubstituted allenyl)benzotriazole 5 was obtained via a stepwise addition of benzophenone to the lithio derivative of 1 followed by a second lithiation and quenching with acetone. Monosubstituted allenes 2a and 8 were cyclized into the benzotriazolyl substituted dihydrofuran 3 and dihydropyrrole 4 respectively.
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