Regioselective Cationic 1,2- and 1,4-Additions Forming Carbon2Carbon Bonds to Methyl Santalbate, a Conjugated Enyne

Ursula Biermann et.al.: Regioselective Cationic 1,2- and 1,4-Additions Forming Carbon2Carbon Bonds to Methyl Santalbate, a Conjugated Enyne

Author(s): Ursula Biermann, Arne Luetzen, Marcel S.F. Lie Ken Jie, Juergen O. Metzger

Title: Regioselective Cationic 1,2- and 1,4-Additions Forming Carbon2Carbon Bonds to Methyl Santalbate, a Conjugated Enyne

Date of Upload: 2000

Article: Eur. J. Org. Chem. 2000, 3069-3073, Department of Chemistry, University of Oldenburg, Carl-von-Ossietzky-Str. 911, 26129 Oldenburg, Germany, Department of Chemistry, The University of Hong Kong,Pokfulam Road, Hong Kong, SAR, China

Keywords: Acylations, Alkylations, Allenes, Enynes, Lewis acids, Methyl santalbate, sustainabel development, renewable feedstock, vegetable oil, plant oil

Abstract:

Lewis acid-induced carbocationic addition reactions to methyl santalbate [methyl (E)-octadec-11-en-9-ynoate] [(E)-1] give products by regioselective formation of a new carbon-carbon bond at C-9 of the molecule chain. The allenic fatty acid derivatives methyl 12-chloro-9-(1-oxoheptyl)- 9,10-octadecadienoate (2) and methyl 9-isopropyl-9,10-octadecadienoate(3) were obtained by Friedel-Crafts acylation of 1 with heptanoyl chloride and alkylation of 1 with isopropyl chloroformate, respectively. While the reaction between 1 and formaldehyde induced by Me₂AlCl or Et₃Al₂Cl₃ gives a mixture of the conjugated chlorodienes 5a and 5b, the corresponding reaction carried out in the presence of AlCl₃ affords the a,b-unsaturated ketone 6.

URL: http://www.chemie.uni-oldenburg.de/oc/metzger/publikationen/pdf/87.pdf (application/pdf)

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