1,3-Dien-5-ynes: Versatile Building Blocks for the Synthesis of Carbo- and Heterocycles

Abstract

ABSTRACT:1,3-Dien-5-ynes have been extensively used as starting materials for the synthesis of a wide number of different carbo-and heterocycles. The aim of this review is to give an overview of their utility in organic synthesis, highlighting the variety of compounds that can be directly accessed from single reactions over these systems. Thus, cycloaromatization processes are initially commented, followed by reactions directed towards the syntheses of five-membered rings, other carbocycles and, finally, heterocycles. The diverse methodologies that have been developed for the synthesis of each of these types of compounds from 1,3-dien-5-ynes are presented, emphasizing the influence of the reaction conditions and the use of additional reagents in the outcome of the transformations.2

Gold‐Catalyzed Cycloisomerizations of Functionalyzed Cyclopropyl Alkynes: the Cases of Carboxamides and Alcohols

“…In this context, we have demonstrated the critical effect of donor‐acceptor substituents in the outcome of gold‐catalyzed reactions of enynes. In this way we have been able to prepare six‐membered heterocycles (pyridines and dihydropyridones) and carbocycles (phenols and terphenyls) from push‐pull conjugated dienynes . On the other hand, alkynyl cyclopropanes have also served as useful starting materials for gold‐catalyzed transformations .…”

Ruthenium‐Catalyzed Cycloisomerization of 2‐Alkynylstyrenes via 1,2‐Carbon Migration That Leads to Substituted Naphthalenes

“…[1,2] Consequently,s ubstantial efforts have been devoted to the development of synthetic routes to various naphthalene skeletons. [3,4] Among these methods, ap articularly powerful and efficient strategy is based on the transition-metal-catalyzed carbon-carbonb ond-forming cycloaromatization [5,6] of benzo-fused 1,3-dien-5-ynes. In the presence of catalytic amount of p-Lewis-acidic metals, such as palladium, [6c,g] platinum, [6a,c,f] gold, [6d,h,i] and zinc, [6c] the benzofused 1,3-dien-5-ynes are converted into naphthalene derivatives without migration of the substituents (Scheme 1a).…”

Nanographene and Graphene Nanoribbon Synthesis via Alkyne Benzannulations

“…30 years, significant optimization of the alkyne benzannulation reaction has led to the discovery of a variety of reagents that promote cyclization in moderate to good yields under relatively mild reaction conditions. There have been numerous examples where π-Lewis acids have been used to activate an alkyne towards cyclization [68,69,70,71,72,73,74,75]. The η 2 -metal complex formed with the alkyne makes it susceptible to nucleophilic attack from the adjacent aromatic ring leading to a new C-C bond.…”

“…Ruthenium catalysts have been shown to be effective at effecting alkyne benzannulations to afford NGs [68,75,76,77,78,79,80,81]. NGs doped with boron and silicon have also been produced using Ru(II) catalysts [82].…”