123-69-3Relevant articles and documents
Efficient and selective formation of macrocyclic disubstituted Z alkenes by ring-closing metathesis (RCM) reactions catalyzed by Mo- or W-based monoaryloxide pyrrolide (MAP) complexes: Applications to total syntheses of epilachnene, yuzu lactone, ambrettolide, epothilone C, and nakadomarin A
Wang, Chenbo,Yu, Miao,Kyle, Andrew F.,Jakubec, Pavol,Dixon, Darren J.,Schrock, Richard R.,Hoveyda, Amir H.
, p. 2726 - 2740 (2013)
The first broadly applicable set of protocols for efficient Z-selective formation of macrocyclic disubstituted alkenes through catalytic ring-closing metathesis (RCM) is described. Cyclizations are performed with 1.2-7.5 mol % of a Mo- or W-based monoaryloxide pyrrolide (MAP) complex at 22 °C and proceed to complete conversion typically within two hours. Utility is demonstrated by synthesis of representative macrocyclic alkenes, such as natural products yuzu lactone (13-membered ring: 73 % Z) epilachnene (15-membered ring: 91 % Z), ambrettolide (17-membered ring: 91 % Z), an advanced precursor to epothilones C and A (16-membered ring: up to 97 % Z), and nakadomarin A (15-membered ring: up to 97 % Z). We show that catalytic Z-selective cyclizations can be performed efficiently on gram-scale with complex molecule starting materials and catalysts that can be handled in air. We elucidate several critical principles of the catalytic protocol: 1) The complementary nature of the Mo catalysts, which deliver high activity but can be more prone towards engendering post-RCM stereoisomerization, versus W variants, which furnish lower activity but are less inclined to cause loss of kinetic Z selectivity. 2) Reaction time is critical to retaining kinetic Z selectivity not only with MAP species but with the widely used Mo bis(hexafluoro-tert-butoxide) complex as well. 3) Polycyclic structures can be accessed without significant isomerization at the existing Z alkenes within the molecule.
Z-SELECTIVE METATHESIS CATALYSTS
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Paragraph 00076; 00078, (2014/07/07)
A novel chelated ruthenium-based metathesis catalyst bearing an N-2,6- diisopropylphenyl group is reported and displays near-perfect selectivity for the Z-olefin (>95%), as well as unparalleled TONs of up to 7,400, in a variety of homodimerization and industrially relevant metathesis reactions. This derivative and other new catalytically-active species were synthesized using an improved method employing sodium carboxylates to induce the salt metathesis and C-H activation of these chelated complexes. All of these new ruthenium-based catalysts are highly Z-selective in the homodimerization of terminal olefins.
Highly active ruthenium metathesis catalysts exhibiting unprecedented activity and Z-selectivity
Rosebrugh, Lauren E.,Herbert, Myles B.,Marx, Vanessa M.,Keitz, Benjamin K.,Grubbs, Robert H.
supporting information, p. 1276 - 1279 (2013/03/14)
A novel chelated ruthenium-based metathesis catalyst bearing an N-2,6-diisopropylphenyl group is reported and displays near-perfect selectivity for the Z-olefin (>95%), as well as unparalleled TONs of up to 7400, in a variety of homodimerization and industrially relevant metathesis reactions. This derivative and other new catalytically active species were synthesized using an improved method employing sodium carboxylates to induce the salt metathesis and C-H activation of these chelated complexes. All of these new ruthenium-based catalysts are highly Z-selective in the homodimerization of terminal olefins.
