Catalytic Meerwein-Ponndorf-Verley (MPV) and Oppenauer (OPP) Reactions: Remarkable Acceleration of the Hydride Transfer by Powerful Bidentate Aluminum Alkoxides

Takashi Ooi, Tomoya Miura, Yoshifumi Itagaki, Hayato Ichikawa, Keiji Maruoka*

*Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan, Email: maruokakuchem.kyoto-u.ac.jp

T. Ooi, T. Miura, Y. Itagaki, H. Ichikawa, K. Maruoka, Synthesis, 2002, 279-291.

DOI: 10.1055/s-2002-19802

Abstract

Bidentate aluminium alkoxides are highly efficient catalysts for the Meerwein-Ponndorf-Verley (MPV) reduction and the Oppenauer (OPP) oxidation in a truly catalytic manner offering highly chemoselective hydride transfer from a secondary alcohol moiety to the remote carbonyl group. The catalytic system is also applicable to high-speed, catalytic Tishchenko reactions.

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Details

The document discusses the development of a highly efficient catalytic procedure for Meerwein–Ponndorf–Verley (MPV) reduction and Oppenauer (OPP) oxidation using bidentate aluminum alkoxides. The new catalyst, (2,7-dimethyl-1,8-biphenylenedioxy)bis(dialkoxyaluminum) (3), significantly accelerates the hydride transfer process, achieving high yields under mild conditions. For instance, the reduction of 4-phenylcyclohexanone with i-PrOH in the presence of 1 mol% of catalyst 3a at room temperature resulted in an 82% yield of 4-phenylcyclohexanol. This method also facilitates the reverse OPP oxidation reaction and enables simultaneous intramolecular reduction/oxidation of hydroxy carbonyl substrates. Additionally, the catalyst 3a is effective in high-speed, catalytic Tishchenko reactions, producing esters from aldehydes with high efficiency. The document highlights the superior performance of bidentate aluminum alkoxides over traditional aluminum catalysts, offering a promising approach for selective and environmentally friendly organic synthesis. The research underscores the potential of bidentate Lewis acid chemistry in developing new synthetic methodologies.

Key Words

Meerwein-Ponndorf-Verley (MPV) reduction, Oppenauer (OPP) oxidation, bidentate aluminum alkoxides, carbonyl compounds, Tishchenko reaction, alcohols

ID: J66-Y2002-1420