Carbon monoxide organoboranes

Scheme 9.1. Homologation and Coupling of Organoboranes by Carbon Monoxide and Other One-Carbon Donors...

If the organoborane is heated with carbon monoxide to 100-125°C, all of the groups migrate and a tertiary alcohol is obtained after workup by oxidation. The presence of water... 

In Scheme 9.1 there are described reactions of organoboranes with cyanide ion, lithiodichloromethane, and dichloromethyl methyl ether. Compare the structures of these reagents and the final reaction products from each of these reagents. Develop a general mechanistic outline with encompasses these reactions, and discuss the structural features which these reagents have in common with one another and with carbon monoxide. 

H. C. Brown, Organoborane-Carbon Monoxide Reactions. A New Versatile Approach to the Synthesis of Carbon Structures, Accounts of Chemical Research 2, 65 (1969). 

Reductive carbonylation and alkylation of imines.3 This cobalt carbonyl catalyzes a reaction of imines with organoboranes and carbon monoxide that results in amides. / -Keto amides are obtained from a-keto imines by this reaction. 

The reaction of organoboranes with carbon monoxide is one of the most versatUe reactions among synthetic applications of organoboranes. Triorganoborane-CO adducts, although not stable enough to be isolated, are isoel Aronic with cyano-trialkylborates. A wide variety of primary, secondary and tertiary alcohols, aldehydes, and ketones have been synthesized by this reaction. Since such reactions have been extensively reviewed only recent progress is presented here. 

TriaikykarUnols from trialkylhoraites. Trialkylcarbinols have been prepared by the reaction of trialkylboranes with carbon monoxide in diglyme followed by oxidation with hydrogen peroxide (equation 1). See 2. 60. The method has the disadvantage that at the temperature required isomerization of organoboranes can be significant. 

Lithium trimethoxyaluminum hydride [1,625, before references]. The reagent greatly enhances the reaction of carbon monoxide with organoboranes.4 The reaction can... 

Carbonylation of organoboranes Carbon monoxide. N,N -Carbonyl-diimidazole. 2,3-Dimethyl-2-butylborane. Hydrogen fluoride—Antimony pentafluoride. Lithium trimethoxyaluminum hydride. Palladium (II) chloride. 

Some interesting developments concerning C-C bond formation using organoborane coupling reactions have been made. 9-Alkyl-9-BBN derivatives (144) react with aryl and benzyl halides in the presence of transition metal catalysts and carbon monoxide to give... 

A useful transformation in synthesis is the reaction of an organoborane to form a carbon-carbon bond. One method to achieve this is by addition of carbon monoxide, followed by oxidation, which can be directed to give primary, secondary or tertiary alcohols, aldehydes or ketones under appropriate conditions. On heating, many... 

The discovery that carbon monoxide reacts with organoboranes under mild... 

These versatile reactions, commonly referred to as Stille and Suzuki couplings, respectively, are performed with organostannanes or organoboranes as nucleophiles and are tolerant to most functional groups. Ketones are obtained if carbon monoxide is present in the Stille reaction. This gives the possibility to label an aromatic methyl ketone in two different positions by the use of either [ C] carbon monoxide or [ C] methyl iodide, as shown in O Fig. 41.22 (Andersson et al. 1995 Andersson and Langstrom 1995a, b). 

Carbon isotopes have played an important role in biological, chemical, medical, and agricultural research. Ironically, the first radioactive isotope of carbon to be used in research was carbon-11," but because of its short half-life (20 min), it was soon displaced by carbon-14 in radiotracer studies. There were two carbon-insertion reactions that appeared to be suited for incorporating carbon isotopes using organoboranes carbon monoxide" " and cyanide ion (Scheme 5.4)." ... 

SCHEME 5.4 The reaction of organoboranes with carbon monoxide and cyanide ion. 

The incorporation of isotopic labels via organoboron chemistry has been the subject of previous communications from Kabalka and co-workers, and two further examples have been reported this year. For example, the preparation of primary alkylamines by the reaction of organoboranes with NH4OH, described in 1981, has now been used to give N-labelled primary amines, and C-labelled carboxylic acids are readily prepared from the reaction of organoboranes with C-enriched carbon monoxide. ... 

Brown, H.C. (1969) Organoborane-carbon monoxide reactions. Synthesis of carbon structures. AcconnWo/C/iemica/ Research, 2,65-72. 

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