The gold(I)-catalyzed cyclization of N-Bocprotected 6-alkynyl-3,4-dihydro-2H-pyridines, prepared by the Sonogashira coupling of lactam-derived enol triflates or phosphates, provides vinylogous amides, which are useful intermediates in the synthesis of natural compounds. The Au(I)-catalyzed reaction is carried out with Ph3PAuOTf as a catalyst and proceeds via a 6-endo-dig cyclization to form a vinylgold species that after protodeauration generates a cyclic carbamate intermediate. This intermediate is in most cases not isolated, but the addition of a base to the reaction mixture rapidly and quantitatively delivers the target vinylogous amide. The first synthesis of a natural compound from Sonneratia hainanensis has been accomplished by this approach.
Synthesis of Vinylogous Amides by Gold(I)-Catalyzed Cyclization of N‑Boc-Protected 6‑Alkynyl-3,4-dihydro‑2H‑pyridines / Alberto Oppedisano; Cristina Prandi; Paolo Venturello; Annamaria Deagostino; Giulio Goti; Dina Scarpi; Ernesto G. Occhiato. - In: JOURNAL OF ORGANIC CHEMISTRY. - ISSN 0022-3263. - STAMPA. - 78:(2013), pp. 11007-11016. [10.1021/jo4019914]
Synthesis of Vinylogous Amides by Gold(I)-Catalyzed Cyclization of N‑Boc-Protected 6‑Alkynyl-3,4-dihydro‑2H‑pyridines
SCARPI, DINA;OCCHIATO, ERNESTO GIOVANNI
2013
Abstract
The gold(I)-catalyzed cyclization of N-Bocprotected 6-alkynyl-3,4-dihydro-2H-pyridines, prepared by the Sonogashira coupling of lactam-derived enol triflates or phosphates, provides vinylogous amides, which are useful intermediates in the synthesis of natural compounds. The Au(I)-catalyzed reaction is carried out with Ph3PAuOTf as a catalyst and proceeds via a 6-endo-dig cyclization to form a vinylgold species that after protodeauration generates a cyclic carbamate intermediate. This intermediate is in most cases not isolated, but the addition of a base to the reaction mixture rapidly and quantitatively delivers the target vinylogous amide. The first synthesis of a natural compound from Sonneratia hainanensis has been accomplished by this approach.File | Dimensione | Formato | |
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