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Synthesis of Heterocycles Mediated by Benzotriazole. 1. Monocyclic Systems

“…Thus, adduct 24 is obtained from a low-temperature reaction of benzotriazole with methyl 2-(trifluoroacetyl)vinyl sulfone ( 23 ). At slightly elevated temperature, adduct 24 eliminates spontaneously methanesulfinic acid to give alkenone 25 in 88% yield . Addition of benzotriazolide anion to the α-carbon of ( E )-(2-phenylvinyl)phenyliodonium tetrafluoroborate ( 26 ) results in unstable benzyl anion 27 , which rapidly eliminates iodobenzene to afford ( E )-1-(2-phenylvinyl)benzotriazole ( 28 ) in 64% yield…”

1,2,3-Triazoles

“…Such is the case of adduct 140 that is obtained from a low temperature reaction of benzotriazole with methyl 2-(trifluoroacetyl)vinyl sulfone. At slightly elevated temperature, adduct 140 eliminates spontaneously methanesulfinic acid to give product 141 <2003RCB1791> . Addition of a benzotriazolide anion to carbon α of ( E )-(2-phenylvinyl)phenyliodonium tetrafluoroborate results in unstable benzyl anion 143 that rapidly eliminates iodobenzene to afford ( E )-1-(2-phenylvinyl)benzotriazole 142 <2002JCM388> .…”