Dicobalt octacarbonyl catalyzed reaction of cyclic ortho esters with a hydrosilane and carbon monoxide. A novel method for homologation of 1,2-, 1,3-, and 1,4-diols

Chatani, Naoto; Kajikawa, Yasuteru; Nishimura, Hideaki; Murai, Shinji

doi:10.1021/om00047a012

Cited by 27 publications

(4 citation statements)

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“…Besides acetates or lactones, cyclic ortho esters also react with CO to afford the corresponding homologues (Table ) . In the case of substituted cyclic ortho esters 41 , highly regioselective ring opening occurs at the primary carbon center as the major products 42 (Table ).…”

Section: Reductive Carbonylationmentioning

confidence: 99%

“…73 Besides acetates or lactones, cyclic ortho esters also react with CO to afford the corresponding homologues (Table 17). 74 In the case of substituted cyclic ortho esters 41, highly regioselective ring opening occurs at the primary carbon center as the major products 42 (Table 18). The stereospecificity of the ring opening reaction has been demonstrated in the siloxymethylation of 44 to yield 45 with an inversion of configuration (eq 31).…”

Section: Reductive Carbonylationmentioning

confidence: 99%

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Transition Metal-Catalyzed Activation of Aliphatic C−X Bonds in Carbon−Carbon Bond Formation

2000

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Section: Reductive Carbonylationmentioning

confidence: 99%

Section: Reductive Carbonylationmentioning

confidence: 99%

Transition Metal-Catalyzed Activation of Aliphatic C−X Bonds in Carbon−Carbon Bond Formation

2000

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“…The oxonium ions undergo reaction with nucleophiles at either C-2 or C-4/5 depending on the nature of the nucleophile . Hard nucleophiles, such as silyl enol ethers, cuprates and titanium enolates, add at C-2 in a kinetically controlled process, whereas soft nucleophiles, such as alcohols and phenols or Co(CO) 4 - anion, add at C-4/5 in a thermodynamic process. Silylated nucleotides react at either site depending on reaction conditions …”

Section: Introductionmentioning

confidence: 99%

Stereoselective and Regioselective Reaction of Cyclic Ortho Esters with Phenols

et al. 2001

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Cyclic ortho esters undergo stereoselective and regioselective reaction with phenols when treated with BF(3) x OEt(2) at low temperatures. Attack of the phenol on the ortho ester occurs at an open carbon para to electron-donating groups on the phenol ("C-addition") or at the phenolic hydroxyl group ("O-addition") depending on the nature of the cation formed from reaction of the ortho ester and BF(3) x OEt(2). Products resulting from O-addition undergo reversion to a mixture of starting phenol, C-addition product, and O-addition product if treated with BF(3) x OEt(2) at room temperature, but C-addition products are stable under the same conditions. X-ray structural analysis of the C-addition compound indicates that its stereochemistry is opposite to that observed in reaction of similar ortho esters with chloride from TMSCl. However, the stereochemistry of the reaction can be rationalized by the ability of the ortho ester to isomerize via an intermediate benzylic cation and examination of the preferred trajectory of attack of the nucleophile on the intermediate oxonium ion.

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“…Early examples of C–O bond activation with cobalt originate from studies of the Pauson–Khand reaction with dicobalt octacarbonyl as a catalyst. − Later, it was demonstrated that Co(II) salts are also catalytically active . To date, the scope of C–O bonds reactive under cobalt catalysis involves acetates (reported by Murai , and Gosmini − ), ortho-esters and lactones (Murai , ), sulfonates (Fuchikami, Knochel, − Gosmini, − Hayashi, , and Weix), allyl ethers (Keiya and Yorimitsu and Oshima), sulfamates, carbamates, phosphates (Ackermann), and benzyl alcohols (Shi). In contrast, aryl methoxides have not been used as substrates in cobalt-catalyzed C–O bond activation so far.…”

Section: Introductionmentioning

confidence: 99%

Cobalt-Catalyzed Formation of Grignard Reagents via C–O or C–S Bond Activation

Pietrasiak

Jeon

et al. 2022

J. Org. Chem.

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C(aryl)–OMe bond functionalization catalyzed by cobalt(II) chloride in combination with a nacnac-type ligand and magnesium as a reductant is reported. Borylation and benzoylation of aryl methoxides are demonstrated, and C(aryl)–SMe bond borylation can be achieved under similar conditions. This is the first example of achieving these transformations using cobalt catalysis. Mechanistic studies suggest that a Grignard reagent is generated as an intermediate in a rare example of a magnesiation via a C–O bond activation reaction. Indeed, an organomagnesium species could be directly observed by electrospray ionization mass spectroscopic analysis. Kinetic experiments indicate that a heterogeneous cobalt catalyst performs the C–O bond activation.

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Dicobalt octacarbonyl catalyzed reaction of cyclic ortho esters with a hydrosilane and carbon monoxide. A novel method for homologation of 1,2-, 1,3-, and 1,4-diols

Cited by 27 publications

References 0 publications

Transition Metal-Catalyzed Activation of Aliphatic C−X Bonds in Carbon−Carbon Bond Formation

Transition Metal-Catalyzed Activation of Aliphatic C−X Bonds in Carbon−Carbon Bond Formation

Stereoselective and Regioselective Reaction of Cyclic Ortho Esters with Phenols

Cobalt-Catalyzed Formation of Grignard Reagents via C–O or C–S Bond Activation

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