Tributylphosphine reaction + carbonyls

Recently, Ohmori and coworkers have used an anodic oxidation reaction to promote the reduction of an acid [34]. In this experiment, the anodic oxidation of triphenyl- or tributylphosphine in the presence of a carboxylic acid led to the formation of an acyl phosphonium ion. The acyl phosphonium ion was then reduced at the cathode to form an ylide which then trapped a second carbonyl... 

The reaction using 11a as a substrate in the presence of several oxides as additives revealed that addition of tributylphosphine oxide, hexamethylphos-phoric triamide, and dimethyl sulfoxide all accelerate the reaction considerably. Furthermore, when about 10 molar amounts of N-methylmorpholine M-oxide (NMO) is added to the alkyne-cobalt complex 12b in THF,the reaction proceeds even at room temperature and cyclopentenone 13 b is obtained in 37% yield accompanied by another rearranged product, the methylenecyclobutanone 35, obtained in 23% yield as a mixture of ( )-and (Z)-isomers (Scheme 14). These facts indicate that dissociation of the carbonyl ligand of the alkyne-cobalt complex 12 is the rate-determining step in this rearrangement. This is also supported by the fact that under a CO atmosphere in refluxing THF the reaction is completely suppressed. 

A basic amine catalyst may promote the self-aldol reaction of the aldehyde, having an enolizable carbonyl. This reaction can be particularly important in the case of slowly reacting hindered aldehydes. In order to avoid this secondary reaction, a number of trialkylphosphines were tested and, in non-asymmetric reactions, tributylphosphine was generally found to be the most effective [32, 33],... 

Jiang and co-workers have utilized the tandem intramolecular Staudinger/aza-Witig reaction as the key step toward their synthesis of marine natural product hamacanthin B (79) and the antipode of hamacanthin A (82).35,36 In these examples, tributylphosphine was utilized to generate intermediate iminophosphoranes that immediately, upon heating, cyclized with the appropriately positioned carbonyl to afford the central ring systems 78 and 81. 

The reaction as originally used employed cobalt compounds as catalysts at temperatures of ca. 150° and > 300 psi pressure, and some three million tons a year of alcohols, usually C7-C9, are produced in this way. The process ordinarily gives both straight- and branched-chain products in the ratio ca. 3 1, but considerable efforts have been made to improve the yield of the linear product patents describe the use of tributylphosphine-substituted cobalt carbonyls for this purpose.60... 

Carbonyls. The reaction of diphenylphosphine with methyl pyruvate gave (27), isolated as the oxide, whereas reaction of tributylphosphine... 

Binuclear Simple Carbonyls. Mechanisms of reactions of the binuclear carbonyls M2(CO)io continue to be a subject of research and discussion. The most recent paper in this field opens with a useful review of current data and opinions, and offers e.s.r. evidence for the intermediacy of radicals in reaction of Mii2(CO)io with tributylphosphine or triethyl-phosphine. Rates of substitution at Mn2(CO)io by poor nucleophiles are decreased by the presence of an excess of carbon monoxide, are independent of nucleophile concentration, and are associated with large positive activation energies. These, and earlier results reported by other workers, can all be accommodated by a mechanism involving reversible loss of carbon monoxide ... 

Treatment of a disilane with CuOTf generates a silyl anion which can add in conjugate fashion to a, -unsaturated carbonyl compounds (eq 111). Optimal conditions consist of heating the reaction mixture in DMF in the presence of tributylphosphine. Absence of the latter gives very low conjugate addition product (20%). 

Dithio-acetals can be prepared from the corresponding carbonyl compound by reaction with a disulphide and tributylphosphine [equation (58)]. Yields of... 

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