944918-34-7Relevant academic research and scientific papers
In Situ Methylene Capping: A General Strategy for Efficient Stereoretentive Catalytic Olefin Metathesis. the Concept, Methodological Implications, and Applications to Synthesis of Biologically Active Compounds
Xu, Chaofan,Shen, Xiao,Hoveyda, Amir H.
supporting information, p. 10919 - 10928 (2017/08/15)
In situ methylene capping is introduced as a practical and broadly applicable strategy that can expand the scope of catalyst-controlled stereoselective olefin metathesis considerably. By incorporation of commercially available Z-butene together with robust and readily accessible Ru-based dithiolate catalysts developed in these laboratories, a large variety of transformations can be made to proceed with terminal alkenes, without the need for a priori synthesis of a stereochemically defined disubstituted olefin. Reactions thus proceed with significantly higher efficiency and Z selectivity as compared to when other Ru-, Mo-, or W-based complexes are utilized. Cross-metathesis with olefins that contain a carboxylic acid, an aldehyde, an allylic alcohol, an aryl olefin, an α substituent, or amino acid residues was carried out to generate the desired products in 47-88% yield and 90:10 to >98:2 Z:E selectivity. Transformations were equally efficient and stereoselective with a ～70:30 Z-:E-butene mixture, which is a byproduct of crude oil cracking. The in situ methylene capping strategy was used with the same Ru catechothiolate complex (no catalyst modification necessary) to perform ring-closing metathesis reactions, generating 14- to 21-membered ring macrocyclic alkenes in 40-70% yield and 96:4-98:2 Z:E selectivity; here too, reactions were more efficient and Z-selective than when the other catalyst classes are employed. The utility of the approach is highlighted by applications to efficient and stereoselective syntheses of several biologically active molecules. This includes a platelet aggregate inhibitor and two members of the prostaglandin family of compounds by catalytic cross-metathesis reactions, and a strained 14-membered ring stapled peptide by means of macrocyclic ring-closing metathesis. The approach presented herein is likely to have a notable effect on broadening the scope of olefin metathesis, as the stability of methylidene complexes is a generally debilitating issue with all types of catalyst systems. Illustrative examples of kinetically controlled E-selective cross-metathesis and macrocyclic ring-closing reactions, where E-butene serves as the methylene capping agent, are provided.
Synthesis of stable and potent δ/μ opioid peptides: Analogues of H-Tyr-c[D-Cys-Gly-Phe-D-Cys]-OH by ring-closing metathesis
Mollica, Adriano,Guardiani, Giovanni,Davis, Peg,Ma, Shou-Wu,Porreca, Frank,Lai, Josephine,Mannina, Luisa,Sobolev, Anatoli P.,Hruby, Victor J.
, p. 3138 - 3142 (2008/02/06)
Ring-closing metathesis has emerged as a powerful tool in organic synthesis for generating cyclic structures via C-C double bond formation. Recently, it has been successfully used in peptide chemistry for obtaining cyclic molecules bridged through an olef
