Silver(I)-Mediated Cascade Reaction of 2-(1-Alkynyl)-2-alken-1-ones with 2-Naphthols

Abstract

An efficient cascade reaction of 2-(1-alkynyl)-2-alken-1-ones with 2-naphthols promoted by silver trifluoroacetate is disclosed, providing an expeditious access to 1,2-dihydronaphtho­[2,1-b]­furans with moderate to good yields. This domino process involves highly regio- and diastereoselective sequential cyclization/nucleophilic addition/oxidative ring opening/oxa-Michael addition reactions to construct three new chemical bonds and one new five-membered ring. A gram-scale experiment and the preliminary results to develop an asymmetric variant are also presented to show the practicality and potential of the current reaction.

The Enantioselective TCDC approach in Au(I)-Catalysis: Insights into the Reactions between 2-Alkynyl Ketones and Naphthols

“…In the last part of our work, we have targeted an asymmetric variant of the -ethynyl-enone cycloisomerization / 2-naphthol addition / oxidation sequence reported by Ren under silver(I) catalysis (see Scheme 1). 10 In this process, the first formed bicyclic furane 5 (naphthol C-addition product) is converted in situ into the chiral cyclohexanone 8 by air oxidation (Scheme 6). Therefore, starting from enone 1a (R 1 = Ph) and 2naphthol 2m, we have applied catalytic conditions favoring the C-addition pathway.…”

“…Scheme 1: Context of this work: enantioselective tandem yneenone cycloisomerization/nucleophilic additions under Ag(I) and Au(I)-catalysis On the other hand, Xu and Ren have reported on analogous tandem reactions involving 2-naphthols as nucleophiles, taking place under silver trifluoroacetate catalysis. 10 These reactions afforded furanes 5 that result from the addition of naphthols as C-centered nucleophiles. The corresponding oxidation products 8 have been isolated as well (Scheme 1, eq.…”

Metal-Free Intramolecular [3+2] Cycloaddition of γ-Hydroxy Acetylenic Ketones with Alkynes for the Synthesis of Naphtho[1,2-c]furan-5-ones and Its Derivatization via a Selective C(sp2)–H Deuteration Reaction

“…Because of their importance, considerable research efforts have been devoted to developing efficient methods for constructing polyfunctionalized naphthofuranones and dihydronaphthofurans. These reported synthetic strategies employed to yield the polycyclic products can be classified into three categories: (1) [3+2] cycloaddition reactions for the formation of a furan moiety from substituted naphthol derivatives with unsaturated hydrocarbons or epoxides, (2) transition-metal-catalyzed tandem cyclization of functionalized alknylbenzenes bearing an oxygen nucleophile, and (3) photoinduced dehydrogenative annulations or intramolecular Friedel–Crafts reactions for the construction of a fused naphthalene ring starting from phenyl-substituted furans. Despite numerous valuable contributions, further development of efficient and novel expeditious methods, including being mild, step and atom economy, and excellent selectivity, still has practical significance.…”

Indium‐Catalysed Transfer Hydrogenation for the Reductive Cyclisation of 2‐Alkynyl Enones towards Trisubstituted Furans

“…Among the numerous synthetic approaches towards furans, the cyclisation of 2‐alkynyl‐substituted 1,3‐conjugated enones 1 with alcohols was first reported by Larock [3] in 2004 (Scheme 1 ) utilising catalytic amounts of gold(III) and various nucleophiles for the synthesis of trisubstituted furans. Further developments by Zhang, Liu, and several other groups (Scheme 1 ) utilising transition metal catalysts, such as gold,[ 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l , 4m , 4n ] palladium,[ 4o , 4p , 4q , 4r ] rhodium, [4s] copper,[ 4t , 4u ] and silver,[ 4v , 4w , 4x ] were reported over the last two decades. In these transition‐metal‐catalysed cyclisation reactions of alkynyl enones of type 1 , a large number of different types of nucleophiles were reported for the synthesis of highly substituted and functionalised furans and annulated bicyclic systems.…”