Reaction of complex ligands: Part 95. Chromium tricarbonyl complexes of polysubstituted naphthohydroquinones: regioselective synthesis via [3+2+1]-benzannulation and haptotropic rearrangement
A series of polysubstituted naphthohydroquinoid tricarbonyl chromiumcomplexes were prepared by chromium mediated [3+2+1]-benzannulation of Fischer-type carbenecomplexes with alkynes. The kinetics and the thermodynamic data of the η6-η6-haptotropic rearrangements were investigated by in-situ NMR spectroscopy. The free activation energies ΔG# range from 23 to 26 kcal mol−1 and only slightly depend
Tetrakispentacarbonyl[(methyleneoxy)phenylcarbene]chromium}methane (3) and tetrakispentacarbonyl[(methyleneoxy)(2-methoxyphenyl)carbene]chromium}methane (4) have been synthesized from tetramethylammonium acylchromate precursors 1 and 2 and pentaerythritol by an acylation/alcoholysis sequence. The X-ray structure analysis of 3 established a distorted-tetrahedral structure, whereas an averaged regular
Syntheses of Naphthoquinone Compounds Using Chromium Carbonyl Carbene Complexes
作者:Masakazu Yamashita、Takahiro Ohishi
DOI:10.1246/bcsj.66.1187
日期:1993.4
The chromium carbonyl carbenecomplexes bearing an acetoxyl group and a phenyl substituent were found to react smoothly with acetylene compounds to produce naphthoquinone derivatives in good yields after oxidation. This cycloaddition reaction proceeded regioselectively and several naphthoquinones were prepared selectively from the complex and unsymmetrical acetylenes.