Reactivity of the [η²‐Bis(tert‐butylsulfonyl)acetylene](carbonyl)(η⁵‐cyclopentadienyl)cobalt Complex Towards Electron‐Rich and ‐Poor Acetylenes

Abstract

Keywords: Alkynes / Cobalt / Cyclopentadienyl ligands / N ligandsThe electron-rich aminoacetylenes Et 2 NC 2 R (2a-c, R = SPh, PPh 2 , and Ph, respectively) react smoothly with [η 2 -bis(tertbutylsulfonyl)acetylene](carbonyl)(η 5 -cyclopentadienyl)cobalt (1) to form the donor-acceptor stabilized (η 4 -cyclobutadiene)cobalt complexes 3a-c in good yields. However, treatment of the electron-poor borylacetylenes 2d-f with the cobalt complex 1 does not lead to the expected (η 4 -cyclobutadiene)cobalt complexes. Analogously, the reaction of bis(1-

Chemistry of the highly stable hindered cobalt sandwich compound (η5-Cp)Co(η4-C4Ph4) and its derivatives

“…Reaction of (A) with butadiynes, bis(methylseleno)butadiyne and (methylthio)(trimethylsilyl)butadiyne resulted in the compounds 309 and 310, respectively, whereas reaction with bis(methylthio)hexatriyne resulted in a dinuclear CpCo-stabilized cyclobutadiene complex 311 bridged by one acetylene moiety as a mixture of two stereoisomers [111]. Sulfur bridged complex 312 was obtained as a single product from the reaction of two equivalents of (A) with (PhC 2 ) 2 S in moderate yield [113].…”

“…Compounds 303 -308 have been synthesized by reaction of (A) with bis(methylseleno)acetylene [111], bis(methyltelluro)acetylene [111], bis(t-butoxy)acetylene [112], 2-(diethylamino)-1-phenylthioacetylene [113], 2-(diethylamino)-1-(diphenylphosphanyl)acetylene [113] and 2-(diethylamino)-1-phenylacetylene [113], respectively. Reaction of (A) with butadiynes, bis(methylseleno)butadiyne and (methylthio)(trimethylsilyl)butadiyne resulted in the compounds 309 and 310, respectively, whereas reaction with bis(methylthio)hexatriyne resulted in a dinuclear CpCo-stabilized cyclobutadiene complex 311 bridged by one acetylene moiety as a mixture of two stereoisomers [111].…”

“…(η 5 -Cp)Co(η 4 -Cb) derivatives having hetero atoms bound to the cyclobutadiene ring[111][112][113][114][115][116][117][118] was of particular interest with both mono-and bis(catecholboryl)acetylenes (having two oxygen atoms attached to boron) resulting in the Co-catalyzed [2+2+2] cyclotrimerization to give benzene derivatives exclusively[119][120][121]. In contrast, reaction of CpCo(CO) 2 with 1-(dithiocatecholboryl)-2-phenylacetylene (having two sulfur atoms attached to boron) and 1-(1,3,2-benzothiaoxaborlolyl)-2-phenylacetylene (having one sulfur and one oxygen atoms attached to boron) resulted in the compounds 321 and 322, respectively, as a mixture of cis/trans isomers[120].…”

Insights into the Molecular Structure and Reactivity of α,ω‐Dialkoxy‐Substituted Ethyne and Butadiyne

“…It was found that diagonal tert-butyl groups are di- Table 2. Comparison of the relevant bond lengths and angles (with standard deviation) of 11, 13 [17] and 14. [18] All distances are given in Å, the angle between the Cp and the Cbd plane is given in°.…”

“…In Table 2 the structural parameters of the cyclobutadiene ring of 11 are compared with those of 13 [17] and 14 (Scheme 5). [18] In the two "push-pull" systems 11 and 13 we find the shortest bond length between C3 and C4 and the longest bond length between C1 and C2.…”