Reactions of Copper and Silver Organoacetylides

Sladkov, A. M.; Gol'ding, I. R.

doi:10.1070/rc1979v048n09abeh002418

Cited by 40 publications

(9 citation statements)

References 17 publications

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“…10 comprises a dimer of [Ti](C⋮CSiMe 3 )(C⋮CAg) fragments in which the C 2 unit in the TiC⋮CAg moiety is additionally η 2 -coordinated to a second silver(I) center, thus forming an alkyne-brigded dimer. The (η 2 -C⋮C) 2 Ag 2 building block has a structural arrangement, which corresponds to that observed in [AgC⋮CR] n …”

Section: Resultssupporting

confidence: 54%

Monomeric Alkyne-Stabilized Complexes of Organo−Copper(I) and −Silver(I)

Lang¹,

Köhler²,

Rheinwald³

et al. 1999

Organometallics

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The synthesis of heterobimetallic {[Ti](C⋮CR1)2}MX {[Ti] = (η5-C5H4SiMe3)2Ti; M = Cu, R1 = SiMe3: 4a, X = SCF3; 4b, X = SEt; M = Ag, R1 = tBu: 5a, X = OC(O)Me; 5e, X = NO3; M = Ag, R1 = SiMe3: 5b, X = OC(O)Me; 5c, X = OC(O)Ph; 5d, X = NO3} is described. These compounds together with {[Ti](C⋮CR1)2}CuX (4c, R1 = SiMe3, X = SC6H4CH2NMe2-2; 4d, R1 = tBu, X = SC6H4CH2NMe2-2) can be used for the preparation of a large variety of different organo−copper(I) and −silver(I) species. The titanium−copper complexes {[Ti](C⋮CR1)2}CuR2 [R1 = SiMe3: 6a, R2 = C6F5; 6b, R2 = C6H2(CF3)3-2,4,6; 6c, R2 = C6H2Ph3-2,4,6; R1 = tBu: 6d, R2 = C6H2Ph3-2,4,6; 7, R2 = Me] are accessible by the reaction of 4c or 4d with suitable organic nucleophiles. Monomeric organo−silver(I) compounds can be prepared by using different starting materials: While the silver(I) aryls {[Ti](C⋮CSiMe3)2}AgR2 [8a, R2 = C6H2(CF3)3-2,4,6; 8b, R2 = C6H2Ph3-2,4,6] are only available by the reaction of 5b with LiC6H2(CF3)3-2,4,6 or BrMgC6H2Ph3-2,4,6, the silver(I) methyl species {[Ti](C⋮CR1)2}AgMe (9a, R1 = SiMe3; 9b, R1 = tBu) can be synthesized by using 5a, 5b, 5d, or 5e as starting materials. While compounds 6−8 are stable under the reaction conditions applied, 9a already starts to decompose at low temperature: The heterobimetallic titanium−silver acetylide {[Ti](C⋮CSiMe3)(C⋮CAg)}2 (10) is formed by nucleophilic substitution of one of the alkynyl Me3Si groups, whereby SiMe4 is eliminated. Moreover, compounds 6−9 react with Br2 to produce R2−Br along with {[Ti](C⋮CR1)2}MBr (M = Cu; 11a, R1 = tBu; 11b, R1 = SiMe3; M = Ag, 11c, R1 = SiMe3), which yield with equimolar amounts of LiR2 or BrMgR2 the starting materials 6−9 back.The solid-state structures of 4a, 5c, 6c, and 8b are reported. All complexes contain a monomeric (η2-alkyne)2M(η1-X) (4, 5) or (η2-alkyne)2M(η1-R2) (6−9) entity in which the group 11 metal atom M is trigonally coordinated by the two alkynyl ligands C⋮CR1 and the η1-bonded groups X or R2, respectively.

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Section: Resultssupporting

confidence: 54%

Monomeric Alkyne-Stabilized Complexes of Organo−Copper(I) and −Silver(I)

Lang¹,

Köhler²,

Rheinwald³

et al. 1999

Organometallics

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“…After appropriate workup, the red precipitate could be identified by its spectroscopic data as polymeric [CuCtC] n (10). 24 As a further product, (Ph 3 P)AuBr ( 11) could be characterized by 31 P{ 1 H} NMR spectroscopic studies and by X-ray crystallography. 25 An explanation for the formation of 10 and 11 in the reaction of 5 with 7b is given by the assumption of the formation of the heterobimetallic intermediate 9 (Scheme 2).…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Coordination Chemistry of Gold(I) Acetylides. The Solid-State Structure of {[η²-(Ph₃P)AuC⋮CFc]Cu(μ-Cl)}₂

et al. 2001

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The gold(I) acetylide (Ph3P)AuC⋮CC6H3(CH2NMe2)2-3,5 (3) is accessible by the reaction of (Ph3P)AuCl (1) with HC⋮CC6H3(CH2NMe2)2-3,5 (2) in a 1:1 molar ratio. Base-catalyzed desilylation of (Ph3P)AuC⋮CSiMe3 (4) produces the homobimetallic gold(I) species (Ph3P)AuC⋮CAu(PPh3) (5). However, the intermediate formation of (Ph3P)AuC⋮CH could not be evidenced, but is most likely. The coordination chemistry of 5 and (Ph3P)AuC⋮CFc (6) toward different copper(I) halides [CuX] n (7a, X = Cl; 7b, X = Br) is presented. While heterodinuclear 6 affords with equimolar amounts of 7a hexanuclear {[η2-(Ph3P)AuC⋮CFc]Cu(μ-Cl)}2 (8), homobinuclear 5 produces with 7b in a 1:1 molar ratio via ligand exchange polymeric [CuC⋮C] n (10) and mononuclear (Ph3P)AuBr (11). A feasible reaction mechanism for the formation of the latter species is presented. The solid-state structure of 8 is reported. It exhibits a linear array around the gold(I) center and a coplanar arrangement of the Cu2Cl2 and the gold(I) acetylide entities.

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“…For a review on bridging ligands in bimetallic alkynyl complexes, see [49]; for [Cu'&i-alkyne)2] in Cu-Pt complexes, see [60]; in Cu-Ir and Cu-Rh; see [40] [50] 1611. The peaks of 2a, 2b, and methyl propargyl cther (7) overlapped with that of the solvent; their mol percentages were not taken into account.…”

Section: ' ) *)mentioning

confidence: 99%

Oligosaccharide Analogues of Polysaccharides. Part 5. Studies on the cross‐coupling of alkynes and haloalkynes

Cai

Vasella

1995

Helvetica Chimica Acta

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(3 1 .VII. 95)The cross-coupling of the homopropargylic ether 1 and the halopropargylic ethers 2a and 2b was optimized, and aspects of the coupling mechanism were studied. Coupling promoted by Pd" and Cu' in the presence of an amine yielded a mixture of the heterodimer 3 and the homodimers 4 and 5 (Scheme I ) . Optimizations were first directed at suppressing homo-coupling. Homo-coupling is partially due to a H/I exchange (1 + 2 a e 6 + 7)promoted by CuI and an amine. The exchange, but not the formation of homodimers, was largely suppressed in DMSO. The influence of phosphine ligands was also evaluated. Weaker g-donors (with the exception of PPh,) lead to a faster coupling and to a higher ratio of hetero-to homodimers, with P(fur), leading to the cleanest reaction. Homodimers are also formed (together with Iz.(i-Pr),NH) by reductive dimerization of the iodoalkyne 2a in the presence of [Pd,(dba),], CuI, and (i-Pr)2NH. Bulky and acceptor-substituted amines reduced the extent of the dimerization of 2a, but the bulkiest amines did not promote coupling. Better results were obtained by using the bromoalkyne 2b. Neither dimerization of 2b, nor H/Br exchange between 1 and 2b were observed. Coupling of 1 and 2b was slower than the one of 1 and 2a, but gave higher yields of the heterodimer 3. The yield of 3 and the ratio of hetero-to homodimers was greatly improved by addition of LiI; no phosphine ligand is then required. While the oxidative addition of the iodoalkync 2a to [Pd(PPh,)J (2a + Sa) was rapid, the one of the bromoalkyne 2b was much slower and proceeded via the $-complex 9 as evidenced by 'H-NMR spectroscopy. The rearrangement of 9 to the bromopalladium 0-complex 8b follows first-order kinetics ( k = 0.014 min-'). CuBr greatly increased the rate of this rearrangement. LiI caused rapid substitution of Br by I in the Pd 0-complex (8b + Sa), but not in 9, nor in 2b. The cJ-complex 8a did not react with the alkyne 1 in the presence of (i-Pr),NH, unless Cu' was added. The alkynes 10 or 1 did not I-eact with CuI and either TMBDA or (i-Pr)ZNH to yield detectable amounts of the Cu-acetylides 11 or 12. These observations are rationalized by the mechanism shown in Scheme 3, postulating the intermediacy of the binuclear alkyne-Pd-Cu complexes C and J, and some or all of E-H, and highlighting the role of Cu' in this coupling.Introduction. -Acetylenosaccharides -analogues of polysaccharides where the glycosidic 0-atom is replaced completely or partially by butadiynediyl moieties [ 1 4 1 -are most efficiently prepared by a binomial synthesis [S] [6], requiring a series of orthogonal deprotections and cross-couplings of saccharide-derived alkynes and haloalkynes.We have reported the regioselective deprotection of diynes and their use in the synthesis of an acetylenosaccharide octamer [4] as well as the synthesis of orthogonally protected dialkynes and of a dimer derived from them [3]. While these reactions proceeded well, the cfciss-euupliiig uf the alkyiies and iudoalkynes yicldcd unly 50-75% uf the desired diynes [24].The C...

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Reactions of Copper and Silver Organoacetylides

Cited by 40 publications

References 17 publications

Monomeric Alkyne-Stabilized Complexes of Organo−Copper(I) and −Silver(I)

Monomeric Alkyne-Stabilized Complexes of Organo−Copper(I) and −Silver(I)

Synthesis and Coordination Chemistry of Gold(I) Acetylides. The Solid-State Structure of {[η²-(Ph₃P)AuC⋮CFc]Cu(μ-Cl)}₂

Oligosaccharide Analogues of Polysaccharides. Part 5. Studies on the cross‐coupling of alkynes and haloalkynes

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Reactions of Copper and Silver Organoacetylides

Cited by 40 publications

References 17 publications

Monomeric Alkyne-Stabilized Complexes of Organo−Copper(I) and −Silver(I)

Monomeric Alkyne-Stabilized Complexes of Organo−Copper(I) and −Silver(I)

Synthesis and Coordination Chemistry of Gold(I) Acetylides. The Solid-State Structure of {[η2-(Ph3P)AuC⋮CFc]Cu(μ-Cl)}2

Oligosaccharide Analogues of Polysaccharides. Part 5. Studies on the cross‐coupling of alkynes and haloalkynes

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Synthesis and Coordination Chemistry of Gold(I) Acetylides. The Solid-State Structure of {[η²-(Ph₃P)AuC⋮CFc]Cu(μ-Cl)}₂