Total Synthesis of Siphonazoles by the Use of a Conjunctive Oxazole Building Block

Abstract

The preparation of 4-carbethoxy-5-methyl-2-(phenylsulfonyl)methyloxazole and its use in the elaboration of more complex oxazoles are described. A total synthesis of the unique natural products, siphonazoles A and B, illustrates an application of the new building block.

CH Alkenylation of Azoles with Enols and Esters by Nickel Catalysis

“…Finally, as a showcase of these new azole alkenylation methods, we applied them to the synthesis of siphonazole B, a natural product isolated from a metabolite from Herpetosiphon sp 3a. Although siphonazole B has already been synthesized by Moody and co‐workers14a,b and Zhang and Ciufolini,14c their syntheses took many steps because of a parallel repetition of linear synthetic sequences. To address this problem, we attempted the convergent synthesis of siphonazole B by using our nickel‐catalyzed CH alkenylation reactions (Scheme ).…”

Muscarine, imidazole, oxazole, and thiazole alkaloids

“…The total synthesis of siphonazoles A 331 and B 332, two conjunctive bis-oxazole natural products isolated from a gliding bacterium of the Herpetosiphon genus, has been recently accomplished by two research groups. [288][289][290] The antifungal isochromanones, ajudazols A 333 and B 334, are a class of structurally unique secondary metabolites from the strain Chondromyces crocatus Cm c5. To study the underlying biosynthetic processes of these isochromanones, the ajudazolproduced gene cluster in C. crocatus Cm c5 was investigated and the biosynthetic pathways for these metabolites deduced.…”

Entdeckung einer Mosaik‐ähnlichen Biosynthesemaschinerie mit einem decarboxylierenden Entladungsmechanismus durch die Kombination von Genom‐Mining und bildgebenden Verfahren

“…Vor einem Jahrzehnt wurde Siphonazol aus Herpetosiphon sp. B060 isoliert, seine Struktur aufgeklärt und Strategien zur vollständigen Synthese entwickelt . Aber Einzelheiten zur Biosynthese einschließlich des zeitlichen Ablaufs und des zugehörigen Genclusters waren bisher unbekannt.…”