Gold-Catalyzed Intermolecular Hetero-Dehydro-Diels−Alder Cycloaddition of Captodative Dienynes with Nitriles:  A New Reaction and Regioselective Direct Access to Pyridines

Abstract

For the first time, nitriles are used as 2pi electron component in a gold-catalyzed intermolecular hetero-dehydro-Diels-Alder cycloaddition with captodative enynes leading to the regioselective formation of pyridines.

Meeting the Challenge of Intermolecular Gold(I)‐Catalyzed Cycloadditions of Alkynes and Allenes

“…39 The formal [4+2] reaction tolerated different substituents on the enyne partner. Furthermore, alkyl and (hetero)aromatic nitriles as well as vinyl nitrile could serve as nucleophilic partners.…”

Recent Strategies for the Synthesis of Pyridine Derivatives

“…[34] This [4 + 2] route provides tetrasubstituted pyridines with Scheme 19. The [4 + 2] synthesis of pyridine derivatives through a rhodium-catalyzed CÀH alkenylation/6p-electrocyclization reaction sequence.…”

“…[40] This [3 + 3] method gives 2,3,6-tri-and 2,3,4,6-tetrasubstitutScheme 23. The [4 + 2] synthesis of tetrasubstituted pyridines reported by Barluenga et al [34] Scheme 24. The [3 + 3] synthesis of pyridines from allenes or acetylenes and alkyl isothiocyanates.…”

Gold‐Catalyzed Addition of Nitrogen and Sulfur Nucleophiles to CC Multiple Bonds

“…(11.20)) [28]. Barluenga and Aguilar have reported an unusual gold(I)-catalyzed hetero-cyclization of dienynes triggered by addition of nitrile to the CÀC triple bond [29]. As an example, treatment of a mixture of dienyne 34 and acrylonitrile with a catalytic 1 : 1 mixture of (Et 3 P)AuCl and AgSbF 6 in DCE at 85 C led to isolation of 2-vinyl pyridine derivative 35 in 75% yield (Scheme 11.4).…”