Ru₃(CO)₁₂-Catalyzed Reaction of 1,6-Diynes, Carbon Monoxide, and Water via the Reductive Coupling of Carbon Monoxide

Abstract

We report the ruthenium-catalyzed cyclization of 1,6-diynes with two molecules of carbon monoxide and water to give a variety of catechols. This reaction likely proceeds through the intermediacy of the water−gas shift reaction to generate an yne− diol-type intermediate followed by a [4 + 2] cycloaddition with 1,6diynes. The reaction requires no external reductants or hydride sources and provides a novel and valuable method for the synthesis of a variety of catechols.

Computational Mechanistic Study of Fused Phenol Formations from 1,6‐Heptadiyne Involving Carbyne Complexes

“…On the other hand, Crudden and coworkers proposed that a ruthenium hydroxycarbyne species is a key intermediate and the coupling between the hydroxycarbyne and CO ligands leading to an η 2 ‐bis(hydroxy)acetylene complex precedes the subsequent reaction with diynes (path B, in Scheme 2). [4a] In the following sections, the reaction of a tungsten carbyne complex, MeC≡WBr(CO) 4 , with 1,6‐heptadiyne was investigated as a model reaction to suggest the reaction mechanism. Subsequently, the reaction of 1,6‐heptadiyne with monometallic ruthenium hydroxycarbyne complexes was analyzed to examine the propose reaction pathway.…”

“…In general, water‐gas shift reaction converts transition‐metal carbonyl complexes, M(CO) n , into the corresponding dihydrido complexes, H 2 M(CO) n –1 , under basic conditions and the initial step is the nucleophilic addition of HO − to one of the CO ligands (Scheme 3a) [19] In contrast, Crudden et al . proposed a water‐gas shift reaction of a ruthenium carbonyl species under neutral conditions as shown in Scheme 3b, [4a] although the addition of less nucleophilic H 2 O requires acidic conditions [20] . Furthermore, it was proposed that dihydridoruthenium carbonyl complex I is converted into monohydridoruthenium hydroxycarbyne complex II , which undergoes carbyne‐CO coupling to generate η 2 ‐dihydroxyacetylene complex IV via ruthenacyclopropene III .…”

“…The Ru≡COH moiety is almost linear, as evidenced by the Ru−C1−OH angle of 172.3°. According to the proposed mechanism, [4a] the coupling of the carbyne and CO ligands was investigated to determine the corresponding transition state ( TS 11 – 12 ). However, the activation barrier is too high (+35.1 kcal/mol) and the formation of the metallacyclopropenone 12 is highly endergonic (+21.1 kcal/mol).…”

Copper-catalysed low-temperature water–gas shift reaction for selective deuteration of aryl halides

“…10 However, due to the high-temperature requirement (>180 °C), applications in organic synthesis remain largely underdeveloped. 11 Herein, we present a heterogeneous copper catalyst, which enables water-gas shift reaction at milder conditions. Thereby, selective deuterodehalogenation of more than 20 diverse aryl bromides is achieved with high deuterium incorporation using of D 2 O/CO (Fig.…”

“… 10 However, due to the high-temperature requirement (>180 °C), applications in organic synthesis remain largely underdeveloped. 11 …”