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Published on: February 7, 2019
Reinvestigation of the reactions of camphorketene: structural evidence for pseudopericyclic pathways
W W Shumway1, N K Dalley, D M Birney
1Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, USA.
Abstract:
The stereochemistry of the dimers (3 and 4) of camphorketene (2) have been determined. The crystal structures of 3, 20 and of related compounds show ground-state distortions that are interpreted as prefiguring planar, pseudopericyclic transition states for retro-cycloadditions to form alpha-oxoketenes. The B3LYP/6-31G* optimized geometry for the transition structure (10) for the dimerization of s-Z-formylketene (8) is consistent with this mechanism. Trapping of 2 with alcohols shows selectivity comparable to other alpha-oxoketenes. The lack of reaction of 2 with benzaldehyde and the lack of enol tautomers in camphoric acid derivatives is attributed to angle strain in the bicyclic camphor moiety.
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