ChemInform Abstract: Asymmetric Synthesis of Highly Functionalized Cyclopentanes by a Rhodium- and Scandium-Catalyzed Five-Step Domino Sequence.

✍ Scribed by Brendan T. Parr; Zhanjie Li; Huw M. L. Davies

• Publisher: John Wiley and Sons
• Year: 2012
• Weight: 83 KB
• Volume: 43
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.201213063

✦ Synopsis

Asymmetric Synthesis of Highly Functionalized Cyclopentanes by a Rhodiumand Scandium-Catalyzed Five-Step Domino Sequence. -Highly functionalized cyclopentanes with four new stereogenic centers are synthesized and obtained as single diastereomers by the present new method involving five distinct steps. In the first step a rhodium-catalyzed oxygen ylide is formed followed by a [2,3]-sigmatropic rearrangement, an oxy-Cope rearrangement, a keto/enol tautomerization, and finally a carbonyl ene reaction. Ketal (IV) is protected under conditions. For the formation of cyclopentane (VII) bearing a silyl ether group higher reaction temperature is required whereas, homologue (VIII) gives the fused pyran derivative (IX) under standard conditions. The present new method can also be applied to optically active diterpenoid (X) giving hydrindane derivatives respective to the catalyst employed. -(PARR, B. T.; LI, Z.;