Recent advances in the tandem annulation of 1,3-enynes to functionalized pyridine and pyrrole derivatives

Abstract

Great progress has been made in the tandem annulation of enynes in the past few years. This review only presents the corresponding reactions of 1,3-enyne structural motifs to provide the functionalized pyridine and pyrrole derivatives. The functionalization reactions cover iodination, bromination, trifluoromethylation, azidation, carbonylation, arylation, alkylation, selenylation, sulfenylation, amidation, esterification, and hydroxylation. We also briefly introduce the applications of the products and the reaction mechanisms for the synthesis of corresponding N-heterocycles.

Proton‐ and halogen‐induced cyclizations of 2‐(3‐butenyl)quinazolin‐4(3H)‐ones in the synthesis of pyrrolo[2,1‐b]‐ and pyrrolo[1,2‐а]quinazolinone derivatives

“…which is well documented in numerous review articles [75][76][77][78][79][80][81][82][83]100]. In view of extending this strategy to 2-homoallylquinazolinones 1, we have studied their reactions with common halogenating agents such as iodine, bromine, N-iodosuccinimide (NIS), and Nbromosuccinimide (NBS).…”

“…Halocyclizations of alkenyl compounds offer a powerful tool for the design of functionalized heterocycles, which is well documented in numerous review articles [75–83, 100]. In view of extending this strategy to 2‐homoallylquinazolinones 1 , we have studied their reactions with common halogenating agents such as iodine, bromine, N‐iodosuccinimide (NIS), and N‐bromosuccinimide (NBS).…”

Synthesis of 2-acetal-1,3-enynes by Sonogashira reaction of bromovinyl acetals with alkynes: application to the formal synthesis of a glucagon antagonist

“…The 1,3-enyne scaffold is found in numerous biologically active natural products 1 and represents a valuable and versatile building block 2 for the synthesis of complex molecules. Therefore, several methods 3 were developed for the preparation of this synthon, including transition metal-catalyzed direct coupling of alkynes 4 or cross-coupling reactions.…”

Aminative annulation of cyano-enynyl esters leading to functionalized cyclopentenones

“…In the past decade, large advancements have been achieved in the annulation of a variety of 1,n-enynes. 1 In this direction, we have extensively studied the annulations of enynes, prepared from different sources, to access functionalized organic molecules. [2][3][4] In particular, a diverse range of functionalized 1,3enynes have been readily generated from Morita-Baylis-Hillman (MBH) adducts (acetates or carbonates) of propiolaldehydes and their annulations leading to the corresponding heterocyclic or carbocyclic frameworks have been studied.…”