Synthesis 2012; 44(13): 2107-2113
DOI: 10.1055/s-0031-1290374
paper
© Georg Thieme Verlag Stuttgart · New York

Asymmetric Synthesis of 3-Substituted Hexahydro-3H-isochromenes via an Organocatalytic Triple Cascade/Yb-Catalyzed Hetero-Diels–Alder Sequence

Nico Erdmann
Institute of Organic Chemisty, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany, Fax: +49(241)8092127   eMail: enders@rwth-aachen.de
,
Iuliana Atodiresei
Institute of Organic Chemisty, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany, Fax: +49(241)8092127   eMail: enders@rwth-aachen.de
,
Dieter Enders*
Institute of Organic Chemisty, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany, Fax: +49(241)8092127   eMail: enders@rwth-aachen.de
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Publikationsverlauf

Received: 25. April 2012

Accepted: 25. April 2012

Publikationsdatum:
04. Juni 2012 (online)


Abstract

An efficient two-step asymmetric synthesis of highly substituted 3-alkoxy-hexahydro-3H-isochromenes and 3-sulfenylated hexahydro-3H-isochromenes is described. The procedure involves an organocatalytic triple cascade reaction, followed by an intermolecular [Yb(fod)3]-catalyzed inverse-electron-demand hetero-Diels–Alder reaction. Using this strategy, a total of six stereogenic centers are obtained with excellent diastereoselectivities and virtually complete enantioselectivities (>95:5 dr, >99% ee).