Preparation of Macrocyclic <i>Z</i>‑Enoates and (<i>E</i>,<i>Z</i>)- or (<i>Z</i>,<i>E</i>)‑Dienoates through Catalytic Stereoselective Ring-Closing Metathesis
2015-12-17T06:04:48Z (GMT) by
The first examples of catalyst-controlled stereoselective macrocyclic ring-closing metathesis reactions that generate <i>Z</i>-enoates as well as (<i>E</i>,<i>Z</i>)- or (<i>Z</i>,<i>E</i>)-dienoates are disclosed. Reactions promoted by 3.0–10 mol % of a Mo-based monoaryloxide pyrrolide complex proceed to completion within 2–6 h at room temperature. The desired macrocycles are formed in 79:21 to >98:2 <i>Z</i>/<i>E</i> selectivity; stereoisomerically pure products can be obtained in 43–75% yield after chromatography. Utility is demonstrated by application to a concise formal synthesis of the natural product (+)-aspicilin.
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