Beilstein Journal of Organic Chemistry (Feb 2013)

Radical zinc-atom-transfer-based carbozincation of haloalkynes with dialkylzincs

  • Fabrice Chemla,
  • Florian Dulong,
  • Franck Ferreira,
  • Alejandro Pérez-Luna

DOI
https://doi.org/10.3762/bjoc.9.28
Journal volume & issue
Vol. 9, no. 1
pp. 236 – 245

Abstract

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The formation of alkylidenezinc carbenoids by 1,4-addition/carbozincation of dialkylzincs or alkyl iodides based on zinc atom radical transfer, in the presence of dimethylzinc with β-(propargyloxy)enoates having pendant iodo- and bromoalkynes, is disclosed. Formation of the carbenoid intermediate is fully stereoselective at −30 °C and arises from a formal anti-selective carbozincation reaction. Upon warming, the zinc carbenoid is stereochemically labile and isomerizes to its more stable form.

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