Treatment of chiral 2<sup>o</sup> alcohols with an alkylmagnesium reagent to form the corresponding magnesium alkoxides, followed by addition of 2-fluorobenzaldehyde resulted in hydride transfer from the alkoxide to the aldehyde. Both the extent of this magnesium version of the Oppenauer oxidation and its stereodifferentiation between alkoxide diastereomers was determined for several different cyclic and acyclic alcohols. After quenching with acid, measured ratios of ketone product to recovered alcohols showed a wide range of overall Oppenauer reactivity, with one alcohol being essentially unreactive while others showed substantial or complete conversion to the corresponding ketone. By measuring the ratio of diastereomers in the recovered alcohols after partial reaction, and comparing to their initial ratio, a range of stereoisomer ratio enhancements was determined. In the example shown here, the stereoisomer ratio increased from 1:1 to as high as 6:1, depending on conditions. For some of the other examples tested, this enhancement revealed a substantial difference in reactivity between the two alkoxide isomers, resulting in nearly complete disappearance of one diastereomer, while much of the other isomer remained unreacted. The effect on reaction outcomes resulting from use of different organomagnesium reagents and solvents was also explored.

Diastereomer differentiation in magnesium-oppenauer oxidation of chiral secondary alcohols

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.