Enantioselective Synthesis of Quebrachamine through an Exceptionally Challenging RCM Reaction

Enantioselective Synthesis of Quebrachamine through an Exceptionally Challenging RCM Reaction 

To address the above reactivity and selectivity problems, a new class of stereogenic-at-[Mo] complexes, represented by monopyrrolide [Mo]-IV, was designed [7a]. The stereogenic-at-[Mo] complex [Mo]-IV, prepared and used in situ from the corresponding achiral Mo-bispyrrohde and a chiral aryl alcohol, readily promotes the difficult RCM. Tetracychc 10 is obtained efficiently in 84% yield and an enantiomeric ratio of 98/2[9j. 

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