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La reaction d'aldehydes avec des diethoxyphosphorylamino-4 benzoates de methyle fournit des aldimines activees qui reagissent, en presence de BF 3 /ether d'ethyle, avec des stannanes allyliques

We review some reactions devised in our laboratory for the rapid assembly of pyridines and pyridones. Applications of the new methods in the total synthesis of lavendamycin, pyridoacridine and phenanthroizidine alkaloids (pyridine chemistry), and of camptothecin, nothapodytine B and streptonigrone (pyridone-forming reactions) are described.

We review methods for the preparation of piperazic acids (“piz”) and significant aspects of their chemistry. Special attention is devoted to issues relating to acylation of these non-proteinogenic amino acids, given the importance of these operations for the synthesis of piz-containing oligopeptides. We also provide an account of the unique conformational properties of piperazic acids and discuss their behavior as rigid proline equivalents that should be quite useful for the creation and study of peptide turn mimics.

A modified Knoevenagel–Stobbe pyridine formation and a thermolytic nitrene insertion are the key steps in a practical new synthesis of lavendamycin methyl ester.

ed from the University of Toronto Ph.D. Thesis L.K. P.L. (1986) and MSc. Thesis of I.A.G. (1983). (3) (a) Jones, J. B.; Beck, J. F. Tech. Chem. (N.Y.) 1976, 10, 107. Jones, J. B. Tetrahedron 1986,42, 3351. (b) Wong, C., H.; Whitesides, G. M. Angew. Chem., Int. Ed. Engl. 1985,24,617. (c) Klibanov, A. M. Science (Washington, D.C.) 1983,219,722; Chem. Technol. 1986, 354. (d) Enzymes in Organic Synthesis, Ciba Foundation Symposium 111; Porter, R., Clark, S., Eds.; Pitman: London, 1985. (e) Biocatalysis in Organic Synthesis; Tramper, J., van der Plas, H. C., Linko, P. Eds.; Elsevier: Amsterdam, 1985. (f) Enzymes as Catalysts in Organic Syn- thesis; Schneider, M., Ed.; Reidel: Dordrecht, Netherlands. (g) Sih, c. J.; Chen, C. S. Angew. Chem., Int. Ed. Engl. 1984,23,570. (h) Butt, S; Roberta, S. M. Natural Products Reports; Royal Society of Chemistry: London, 1986; pp 489-503. (i) Sariaslanc, F. S.; Rosazza, J. P. N. Enz. Microb. Technol. 1984, 6, 242. (4) Abbreviations used: HLADH, horse

A palladium-promoted intramolecular arylation of a β-diketone generates a spirocyclic system as a model for Fredericamycin A.

N-Acyl 2-furylamines were transformed into 2-alkyl-6-methoxy-hexahydropyridin-3-ones. The rearranged products are useful building blocks for the total synthesis of alkaloids and unusual aminoacids.

La reaction d'aldehydes avec des diethoxyphosphorylamino-4 benzoates de methyle fournit des aldimines activees qui reagissent, en presence de BF 3 /ether d'ethyle, avec des stannanes allyliques

Dihydropyrans obtained by cyclocondensation of aromatic enones with vinyl ethers are transformed into pyridines by treatment with hydroxylamine hydrochloride.

A palladium-promoted intramolecular arylation of a β-diketone generates a spirocyclic system as a model for Fredericamycin A.

N-Acyl 2-furylamines were transformed into 2-alkyl-6-methoxy-hexahydropyridin-3-ones. The rearranged products are useful building blocks for the total synthesis of alkaloids and unusual aminoacids.

We describe a concise entry to benzazocenols intermediates, e.g. I, for mitomycinoids via a homo-Brook rearrangement-ring opening sequence of a silylated aziridine, e.g. II. The latter is obtained by intramol. 1,3-dipolar cycloaddn. of an azide with an allylsilane, followed by irradn. of the resulting triazoline.

Dihydropyrans obtained by cyclocondensation of aromatic enones with vinyl ethers are transformed into pyridines by treatment with hydroxylamine hydrochloride.

A modified Rapoport procedure was used to synthesize a tripeptide containing N-methyl-3-hydroxyvaline, an unusual aminoacid found in Luzopeptins.