Organobismuths

In a manner similar to phosphoms, arsenic, and antimony, the bismuth atom can be either tri- or pentacovalent. However, organobismuth compounds are less stable thermally than the corresponding phosphoms, arsenic, or antimony compounds, and there are fewer types of organobismuth compounds. For example, with R MX, R3MX2, R2MX3, and RMX, where M is a Group 15 (VA) element and X is a halogen, only the first two types have been prepared where M = Bi, but all four types are known where M = P, As, or Sb. 

The chemistry of organobismuth compounds has been described in several pubHcations (28—31). The use of organobismuth compounds, as well as organoantimony ones, in organic synthesis has been exhaustively reviewed (32). 

The secondary bismuthides discussed herein are useful for preparing several types of organobismuth compounds, eg, tertiary bismuthines and dibismuthines. 

Diarylbismuthinic Acids and Their Esters. Although organobismuth(V) compounds containing three, four, or five Bi—C bonds are well-known, no compounds containing two such bonds had been prepared until a number of methyl diarylbismuthinates (diarylmethoxybismuth oxides) were reported ia 1988 (145). 

Quaternary bismuth compounds have not found extensive use ia industry or ia organic synthesis. In manifold studies of organobismuth(V) compounds as oxidi2ing and arylating agents, such quaternary bismuth compounds as (CgH )4Bi02CCH2, (CgH )4Bi02SCgH4CH2-4, and... 

Bismuth compounds were once employed for the treatment of amoebic dysentery, certain skin diseases, and several spirochetal diseases besides syphilis, but these substances are now seldom considered the dmgs of choice. Various insoluble preparations of bismuth, especially the subcarbonate, subnitrate, subgaHate, subcitrate, and subsahcylate, are stiU employed for the treatment of ulcers and other gastrointestinal disorders, even though use for these purposes is often supported largely by tradition. With a few possible exceptions, it is now difficult to justify the presence of bismuth compounds in a modem therapeutic armamentarium. A review of the biological activity of organobismuth compounds has been pubHshed (179). 

Sparteine 1 was also used in a palladium complex-catalyzed enantios-elective benzoylation of alcohols using monoxide and the organobismuth(V) compound (Scheme 37). The carbonylative acylation of alcohols using carbon monoxide (CO) is known to be an alternative tool for the prepar-... 

Suzuki, H., and Matano, Y. (2001). Organobismuth Chemistry. Elsevier, Amsterdam. 

Scheme 3 Reaction sites of organobismuth(V) reagents in C-C and C-X bond forming reactions (a) alkenylbismuthonium salt (b) alkynylbismuthonium salt (c) bismuth ylide (d) bismuth imide. Nu nucleophile, B base, El electrophile...

Organobismuth(V) compounds are potential oxidants because of their inherent oxidizing ability, which derives from the facile Bi(V)/Bi(III) redox process [72], This characteristic property of bismuth has been utilized for alcohol oxidation... 

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