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On the preparation and determination of configurational stability of chiral thio- and bromo[D1]methyllithiums.

ABSTRACT: Thio- and bromo[D(1)]methyllithiums (ee 99%) were generated from the respective stannanes by tin-lithium exchange at temperatures ranging from 0 to -95 °C. Thio[D(1)]methyllithiums 6 were found to be microscopically configurationally labile on the time scale of the thiophosphate-α-mercaptophosphonate rearrangement even at -95 °C. Thio[D(1)]methyllithiums 13a and 13b underwent a thia-[2,3]-Wittig rearrangement down to -95 °C and 13b only down to -50 °C. The former were microscopically configurationally stable below -95 °C, and the latter racemized completely at -50 °C. Chiral bromo[D(1)]methyllithiums are chemically unstable at -78 °C but microscopically configurationally stable at the time scale of their addition to benzaldehyde and acetophenone.

SUBMITTER: Wieczorek A

PROVIDER: S-EPMC3557930 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature

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On the preparation and determination of configurational stability of chiral thio- and bromo[D1]methyllithiums.

Wieczorek Anna A Hammerschmidt Friedrich F

The Journal of organic chemistry 20121030 22

Thio- and bromo[D(1)]methyllithiums (ee 99%) were generated from the respective stannanes by tin-lithium exchange at temperatures ranging from 0 to -95 °C. Thio[D(1)]methyllithiums 6 were found to be microscopically configurationally labile on the time scale of the thiophosphate-α-mercaptophosphonate rearrangement even at -95 °C. Thio[D(1)]methyllithiums 13a and 13b underwent a thia-[2,3]-Wittig rearrangement down to -95 °C and 13b only down to -50 °C. The former were microscopically configurati ...[more]

PMID: 23106613

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