Bismuthine imides

The reaction of triphenylbismuth carbonate with cyclic 1,3-dicarbonyl compounds, such as dimedone and Meldrum s acid, gives highly stabilized triphenylbismuthonium ylides (Section 3.5.1). Moderately stabilized acyclic bismuthonium ylides can be prepared from triphenylbismuth dichloride and a 1,3-diketone or a 1,3-disulfone in the presence of a suitable base. A similar base-promoted reaction of triphenylbismuth dihalides with Al-sulfonylamines or amides has been used for the preparation of stabilized bismuthine imides bearing the Af-sulfonyl or Af-acyl moiety (Section 3.6.1). 

Crystalline bismuthine imides bearing an A-sulfonyl group have been prepared by the condensation of triphenylbismuth difluoride with A,A-bis(tri-methylsilyl)sulfonamides or of triarylbismuth dichloride with sulfonamides [93JFC(63)179]. The latter combination is also applicable to the synthesis of trianylbismuthine A -acylimides [99OM2580]. 

The oxazoline-substituted bismuthine imide has a distorted trigonal bipyr-amidal structure, bearing three ipso carbon atoms at equatorial sites and two nitrogen atoms at apical sites with a Bi-N(imide) bond length of 2.13( 1) A and... 

Bis(4-methylphenyl)bismuth A -(4-methylphenyl)sulfonylamide 4 is obtained in moderate yield by the reaction of tris(4-methylphenyl)bismuth [A -(4-methylphenyl)sulfonyl]imide with anise alcohol or cinnamyl alcohol [96JCR(S)24]. This amide is insoluble in benzene, but soluble in chloroform, and not so sensitive to oxygen md moisture in the solid state. However, it slowly decomposes to tris(4-methylphenyl)bismuthine and a white powdery deposit when the amide is stood in CDCI3. 

Triarylbismuthine A -tosylimides react with benzaldehyde, benzoyl chloride and phenyl isocyanate to give A -tosylimine, A-tosylamide and A -tosylurea derivatives, respectively [91CL105] (Section 5.5.2.3). The imides oxidize secondary and benzylic alcohols to carbonyl compounds, sometimes accompanied by the concurrent formation of a diaryl(A -tosylamino)bismuthine [96JCR(S)24] (Section 5.2.4). When treated with acetic acid, the imides are converted to the corresponding triarylbismuth diacetates and sulfonamides (Scheme 3.9). 

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