Synthesis Of Erythronolide Research Articles

Catalytic Asymmetric Synthesis of Complex Polypropionates: Lewis Base Catalyzed Aldol Equivalents in the Synthesis of Erythronolide B

Powerful aldol reactions: Stereoselective Lewis base catalyzed aldol equivalents expediently provided eight of the ten stereocenters required for the synthesis of erythronolide B. Indeed, all eleven stereocenters present in the erythromycin aglycone have been derived directly or indirectly from catalytic asymmetric equivalents of aldol addition reactions (see scheme).

Catalytic Asymmetric Synthesis of Complex Polypropionates: Lewis Base Catalyzed Aldol Equivalents in the Synthesis of Erythronolide B

Catalytic Asymmetric Synthesis of Complex Polypropionates: Lewis Base Catalyzed Aldol Equivalents in the Synthesis of Erythronolide B

NEW APPROACH TO A CLASSIC STRUCTURE

THE NATURAL PRODUCT erythromycin has long been a challenging target for synthetic organic chemists. An efficient and versatile strategy just developed for forming its large ring shows that the antibiotic remains a test bed for innovative approaches that could aid the syntheses of other natural products and analogs. The first synthesis of erythronolide B, an erythromycin precursor, was accomplished in 1978 by Harvard University chemistry professor E. J. Corey. Many other groups have synthesized the erythronolides and erythromycin since then. In all these syntheses, creating the large central ring has always been carried out by acylation-based macrolactonization—a ring-closing esterification between an acyclic precursor’s hydroxyl and carboxyl groups. Now, associate professor of chemistry M. Christina White and graduate student Erik M. Stang of the University of Illinois, Urbana-Champaign, report a radically different approach ( Nat. Chem., DOI: 10.1038/nchem.351). Their work marks the first use of a highly...

Synthesis of Erythronolide

Synthesis of Erythronolide

A novel dioxabicyclo[3.3.1]nonane, a key intermediate in the synthesis of erythronolide B seco-acid.

In the title compound, (1R,4S,5R,6R,8R)-1-ethyl-4,6,8-trimethyl-2,9-dioxabicyclo[3.3.1]++ +nonan-6-yl 1-imidazolecarboxylate, C16H24N2O4, the 2,9-dioxabicyclo[3.3.1]nonane ring system assumes a double-chair conformation. Bond angles around the ring are enlarged compared to normal tetrahedral values to alleviate some of the overcrowding which results from close intramolecular H...H and C...C contacts. The N-imidazolylcarbonyloxy group is nearly planar with dihedral angles of 5.2 (2) and 6.0 (2) degrees between the imidazole and carbonyl groups for molecules 1 and 2, respectively.

Chiral synthesis of polyketide-derived natural products. 38. Synthesis of Erythronolide A via Direct Macrolactonization of a Conformationally Controlled Seco-acid with the Yamaguchi Reagent in the Presence of Dimethylaminopyridine.

Chiral synthesis of polyketide-derived natural products. 38. Synthesis of Erythronolide A via Direct Macrolactonization of a Conformationally Controlled Seco-acid with the Yamaguchi Reagent in the Presence of Dimethylaminopyridine.

ChemInform Abstract: Synthesis of Macrolides.

In order to establish a simple common methodology for the highly stereoselective and efficient synthesis of macrolide aglycones, 12-membered ring methynolide and 16-membered ring tylonolide were synthesized from D-glucose via the synthesis of respective fragments followed by their coupling (esterification by the Yamaguchi method) and cyclization by the Wittig-Horner reaction under Nicolaou's conditions. This method was extended to the synthesis of 14-membered ring pikronolide and, together with conformational control of macrolide rings, to some typical 16-membered ring aglycones such as carbonolides, leuconolides, maridonolides, etc. A new synthesis of erythronolide A via an extremely efficient macrolactonization by virtue of conformational control and super activation of the seco-acid is also described.

マクロリドの合成 高い選択性と効率をもった易しい合成法を確立するために

In order to establish a simple common methodology for the highly stereoselective and efficient synthesis of macrolide aglycones, 12-membered ring methynolide and 16-membered ring tylonolide were synthesized from D-glucose via the synthesis of respective fragments followed by their coupling (esterification by the Yamaguchi method) and cyclization by the Wittig-Horner reaction under Nicolaou's conditions. This method was extended to the synthesis of 14-membered ring pikronolide and, together with conformational control of macrolide rings, to some typical 16-membered ring aglycones such as carbonolides, leuconolides, maridonolides, etc. A new synthesis of erythronolide A via an extremely efficient macrolactonization by virtue of conformational control and super activation of the seco-acid is also described.

Synthesis of erythronolide a via a very efficient macrolactonization under usual acylation conditions with the Yamaguchi reagent

Macrolactonization of 3,5- O-(3,4-dimethoxybenzylidene)-9,11- O-(2,4,6-trimethylbenzylidene)(9 S)-9-dihydroerythronolide A seco-acid ( 4) was reexamined under various conditions and found to proceed rapidly only by treatment of 4 with Yamaguchi's reagent, 2,4,6-trichlorobenzoyl chloride, in the presence of a large excess of TEA and a small amount of DMAP at room temperature to give the corresponding 14-membered erythronolide A derivative ( 7) in almost quantitative yield.

Synthesis of macrolide antibiotics. 18. Stereospecific building up of the carbon chain of erythronolide B

A stereodirected synthesis of erythronolide B carbon chain was carried out starting from from levoglucosan.

Synthesis of macrolide antibiotics. 15. Stereodirected synthesis of erythronolide B according to the coupling scheme of the (C9-C13) + (C7-C8) + (C1-C6) fragments

A stereodirected synthesis of erythronolide B from levoglucosane by coupling the C9-C13) + (C7-C8) + (C1-C6) fragments was carried out.

Structure of an epimeric aldol intermediate toward the synthesis of erythronolide A

C 25 H 35 NO 6 cristallise dans le systeme monoclinique avec le groupe d'espace P2 1 . Affinement de la structure jusqu'a 0,0574