Recent Optimization Highlights of the Georgywood Process

Authors

  • Jean-Pierre Barras
  • Bernadette Bourdin
  • Fridtjof Schröder

DOI:

https://doi.org/10.2533/chimia.2006.574

Keywords:

1,5-diene cyclization, 1,4-elimination, Georgywood, Homomyrcene, Methylaluminum dichloride

Abstract

Alternative procedures to the industrial process by which Georgywood® is presently prepared on a multiton scale have been investigated. These give the crucial homomyrcene precursor 5a and target compound 1 with greatly improved selectivities. Homomyrcene 5a was prepared with much better yield and selectivity by converting methylgeraniol 4 into an allylic carbonate, followed by a solvent-free palladium-catalyzed 1,4-elimination. In the final 1,5-diene cyclization, excellent selectivities were achieved by replacing Brønsted acid H3PO4 by meAlcl2. This requires preparation, safety measures and an in-situ conversion of stoichiometric amounts of the pyrophoric Lewis acid. Recently, an in situ preparation of MeAICI2 from AIMe3 and its catalytic use became possible.

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Published

2006-09-01

Issue

Section

Scientific Articles

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