The enol form of (+)-(1R,4R)-3-benzoylcamphor

Abstract

In the crystalline state, the mol­ecule of the title compound, (+)‐(1R,4R)‐3‐(hydr­oxybenzyl­idene)‐1,7,7‐trimethylbicyclo[2.2.1]heptan‐2‐one, C17H20O2, exists in the enolized form, with the H atom located on the phenyl‐substituted C—O fragment rather than on the camphoryl‐substituted one. The enolic H atom is involved in intra­molecular hydrogen bonding [O⋯O = 2.633 (2) Å].

The diketo form of (+)-(1R,4R)-3-benzoylcamphor

“…1), in which the central C-C and C-O bond lengths are typical for single and double bonds, respectively. In contrast to the structure of the previously reported enol tautomer (Niemeyer & Gan, 2005) which shows an almost planar five-membered C 3 O 2 ring, the two carbonyl groups in (I) are considerably twisted. The latter fact is reflected by the dihedral angles between the central C 3 plane, defined by atoms C2, C3 and C11, and the O2/C2/C3 [13.1 (4) ] and C3/C11/O1 [61.6 (2) ] planes.…”

“…3-Benzoylcamphor is a rare example of a structurally characterized -diketone that crystallizes both in the diketo and the enol forms. According to density functional theory (DFT) calculations, the diketo tautomer is destabilized by 17.4 kJ mol À1 over the previously reported [Niemeyer & Gan (2005). Acta Cryst.…”

“…(+)-(1R,4R)-3-Benzoylcamphor was prepared as described previously (Cullen et al, 1988;Niemeyer & Gan, 2005) from (+)-(1R,4R)-3bromocamphor and ethyl benzoate. Whereas crystallization from petroleum ether afforded the pure enol tautomer, use of methanol as solvent produced a mixture of colourless blocks of the enol form and needle-shaped crystals of the diketo tautomer that were suitable for X-ray studies (m.p.…”

“…The Ce III -catalysed -hydroxylation of -diketo compounds with molecular oxygen is a mild atom-economic and environmentally friendly method for the synthesis of the biologically important -hydroxy--dicarbonyl group (Christoffers & Werner, 2002;Christoffers et al, 2003Christoffers et al, , 2004Rö ssle et al, 2004). The structure determination of the title compound, (I), was performed as a part of a project on the preparation of well defined chiral metal camphorates (Niemeyer & Gan, 2005;Seo and Niemeyer, 2006) which might be used for enantioselective oxidation reactions.…”

trans-Bis[(+)-(1R,4R)-3-benzoylcamphorato-κ2O,O′]copper(II)

“…The Ce III -catalysed -hydroxylation of -diketo compounds with molecular oxygen is a mild atom-economic and environmentally friendly method for the synthesis of the biologically important -hydroxy--dicarbonyl group (Christoffers & Werner, 2002;Christoffers et al, 2003Christoffers et al, , 2004Rö ssle et al, 2004). The structure determination of the title compound, (I), was performed as part of a project on the preparation of well defined chiral metal camphorates (Niemeyer & Gan, 2005; which might be used for enantioselective oxidation reactions.…”