P. Langer et al., Regioselective anionic [3+2] cyclizations of imidazole dinucleophiles withoxaldiimidoyl dichlorides - A combined experimental and theoretical study, EUR J ORG C, (12), 2001, pp. 2245-2255
Regioselective cyclization reactions between oxaldiimidoyl dichlorides and
imidazole-derived dinucleophiles provide convenient access to biologically
relevant diazabicyclo[2.2.1]heptanones, 1H-pyrrolo[ 1,2-alpha ]benzimidazol
es, 3H-imidazo[1,2-alpha ]benzimidazoles and 2,3-dihydrothiazolo[3,2,alpha
]benzimidazoles. All cyclizations proceed with good regioselectivity, direc
ted by the heteroatoms of the dinucleophile. The tautomeric forms of the st
ructurally mobile benzimidazoles have been studied both in solution and in
the solid state. The structural properties and the regioselectivities are e
xplained by semiempirical calculations.