Beilstein J. Org. Chem.2019,15, 1475–1479, doi:10.3762/bjoc.15.148
G. K. Surya Prakash Golam Rasul Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, University Park, Los Angeles, CA 90089-1661, USA 10.3762/bjoc.15.148 Abstract The structures of the elusive cyclobutanedication, (CH2)42+, were investigated at the
considered as a prototype for a 2e-4c Woodward–Hoffmann frozen transition state. The planar rectangular shaped structure 2 with a 2e-4c bond was found not to be a minimum.
Keywords: cyclobutanedication; 2e-4c bond; frozen transition state; Woodward–Hoffmann rule; Introduction
The protonated hydrogen
+, v) and the cyclobutanedication (CH2)42+ (vi)?
The structures of H42+ (including v) were previously analyzed at various theoretical levels including CISD/6-311++G(d,2pd) by von Ragué Schleyer, Koch and co-workers [9]. No structure with four connected hydrogens, however, was found to be a minimum on
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Graphical Abstract
Scheme 1:
Examples of 2e-3c and 2e-4c bonded structures.