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Z-Trisubstituted α,ß-Unsaturated Esters and Acid Fluorides through Stereocontrolled Catalytic Cross-Metathesis.
Qin, Can; Koengeter, Tobias; Zhao, Fengyue; Mu, Yucheng; Liu, Fang; Houk, K N; Hoveyda, Amir H.
Afiliación
  • Qin C; Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States.
  • Koengeter T; Supramolecular Science and Engineering Institute, University of Strasbourg, CNRS, 67000 Strasbourg, France.
  • Zhao F; Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States.
  • Mu Y; College of Sciences, Nanjing Agricultural University, Nanjing 210095, China.
  • Liu F; Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States.
  • Houk KN; College of Sciences, Nanjing Agricultural University, Nanjing 210095, China.
  • Hoveyda AH; Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States.
J Am Chem Soc ; 145(6): 3748-3762, 2023 Feb 15.
Article en En | MEDLINE | ID: mdl-36720176
ABSTRACT
Catalytic cross-metathesis (CM) reactions that can generate trisubstituted alkenes in high stereoisomeric purity are important but remain limited in scope. Here, CM reactions are introduced that generate Z-trisubstituted α-methyl, α,ß-unsaturated, alkyl and aryl esters, thiol esters, and acid fluorides. Transformations are promoted by a Mo bis-aryloxide, a monoaryloxide pyrrolide, or a monoaryloxide chloride complex; air-stable and commercially available paraffin tablets containing a Mo complex may also be used. Alkyl, aryl, and silyl carboxylic esters as well as thiol esters and acid fluoride reagents are either purchasable or can be prepared in one step. Products were obtained in 55-95% yield and in 8812->982 Z/E ratio (typically >955). The applicability of the approach is highlighted by a two-step conversion of citronellol to an isomintlactone precursor (1.7 g, 73% yield, and 973 Z/E) and a single-step transformation of lanosterol acetate to 3-epi-anwuweizic acid (72% yield and 946 Z/E). Included are the outcomes of DFT studies, regarding several initially puzzling catalyst activity trends, providing the following information (1) it is key that a disubstituted Mo alkylidene, generated by a competing homo-metathesis (HM) pathway, can re-enter the productive CM cycle. (2) Whereas in a CM cycle the formation of a molybdacyclobutane is likely turnover-limiting, the collapse of related metallacycles in a HM cycle is probably rate-determining. It is therefore the relative energy barrier required for these steps that determines whether CM or HM is dominant with a particular complex.

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Idioma: En Revista: J Am Chem Soc Año: 2023 Tipo del documento: Article País de afiliación: Estados Unidos

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Idioma: En Revista: J Am Chem Soc Año: 2023 Tipo del documento: Article País de afiliación: Estados Unidos
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