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Synthesis 2007(15): 2279-2286  
DOI: 10.1055/s-2007-983781
PAPER
© Georg Thieme Verlag Stuttgart · New York

Stereoselective Heck-Matsuda Arylations of Chiral Dihydrofurans with Arenediazonium Tetrafluoroborates; An Efficient Enantioselective Total Synthesis of (-)-Isoaltholactone

Paulo Roberto Rodrigues Meira, Angélica Venturini Moro, Carlos Roque Duarte Correia*
Instituto de Química, Universidade Estadual de Campinas, UNICAMP, C.P. 6154, CEP 13084-971, Campinas, São Paulo, Brazil
Fax: +55(19)35213086; e-Mail: roque@iqm.unicamp.br;
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Publikationsverlauf

Received 1 March 2007
Publikationsdatum:
12. Juli 2007 (online)

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Abstract

The Heck-Matsuda arylation of chiral 2-(S)-hydroxy­methyl dihydrofurans (endocyclic enolethers) and its derivatives, employing arenediazonium tetrafluoroborates, was developed into a highly efficient, practical and diastereoselective synthetic process. This methodology was applied to the total synthesis of the styryllactone (-)-isoaltholactone in seven steps with an overall yield of ˜25%, from the readily available chiral 2-hydroxymethyldihydrofuran. The strategy permits the synthesis of several other aromatic analogues of isoaltholactone.

Key words

Heck reaction - palladium - diazonium compounds - catalysis - stereoselectivity

9

The endocyclic enolether 12 is a rather volatile compound. Use of reduced pressure should be avoided during its isolation and purification.

10

An interesting alternative to the use of dihydrofuran is the use of a balloon of carbon monoxide. A dark blue solution forms after a few minutes of exposure which stays stable for a long time, without any signs of Pd precipitation. However, upon addition of the remaining reagents, formation of Pd black begins to occur in the reaction medium.