Synthesis 2009(16): 2778-2784  
DOI: 10.1055/s-0029-1216898
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

A Regioselective Tsuji-Trost Pentadienylation of 3-Allyltetronic Acid

Rainer Schobert*, Bertram Barnickel
Organisch-chemisches Laboratorium der Universität Bayreuth, Gebäude NW I, 95440 Bayreuth, Germany
Fax: +49(921)552671; e-Mail: Rainer.Schobert@uni-bayreuth.de;
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Publikationsverlauf

Received 16 March 2009
Publikationsdatum:
14. Juli 2009 (online)

Abstract

A regioselective Tsuji-Trost reaction of sodium 3-allyl-tetronate with methyl 5-trimethylsilylpenta-2,4-dienyl carbonate was developed. Carbon-carbon bond formation at the more highly substituted terminus of the pentadienyl residue was possible by introduction of an easy to remove SiMe3 shielding group at the remote end of the π-system. This carbonate reacted fast enough to avoid scrambling and formation of symmetric bisallyl tetronic acids. The 3-allyl-3-penta-2,4-dienyltetronic acid thus obtained is a key intermediate en route to the natural spirolactone bakkenolide A.