ISSN:
0009-2940
Keywords:
Benzoxazaphosphorinones
;
Rearrangements
;
Ring-expansion reaction
;
Insertion reaction
;
Gold complex
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Reaction of some Dihydrobenzoxazaphosphorinones with Nucleophiles; Unusual Oxidation, Insertion, and Rearrangement Products and their Characterisation by Single-Crystal X-Ray AnalysisThe reaction of 2-chloro-1,2-dihydro-1-methyl-4H-3,1,2-oxazaphosphorin-4-one (2) and its 2-diethylamino-substituted derivative 3 with various nucleophiles yielded novel and sometimes unexpected products. Hydrolysis of 2 furnished the 2-hydroxybenzoxazaphosphorinone 4. In the presence of small amounts of water, two molecules of 4 were transformed into 5, accompanied by cleavage of one of the heterocyclic rings. The reaction of 2 with sodium chlorodifluoroacetate led, possibly in an Arbuzov-type reaction, to compound 6. The 1,5-diaza-4,8-cyclooctanedione system 7 was formed by reaction of 2 with 1,2,4,5-tetrakis(trimethylsilyloxy)benzene with concomitant loss of the phosphorus-containing group. 2,2′-Bis(trimethylsiloxy)biphenyl reacted with 2 in the expected fashion to form the diphosphorus compound 8. From 8 the chlorogold(I) complex 9 was obtained. The reaction of 3 with tetrachloro- and tetrabromo-o-benzoquinone did not lead to the expected spirocyclic products by oxidative addition of the quinone system to λ3P. Instead, cleavage and expansion of the heterocyclic ring system with formation of the tricyclic derivatives 10 and 11 took place. Compounds 5-10 were subjected to X-ray structure analysis. Compound 5 exists as two modifications 5a and 5b, which differ mainly in the relative orientation of the phenyl rings; intramolecular N-H…O hydrogen bonds are observed. Bond lengths at the halo-substituted carbon atom in 6 indicate steric crowding. The central 8-membered ring of 7 displays a “tub” conformation. Compound 8 undergoes a conformational change on complexation to the two gold(I) centres; one of the torsion angles C-O(exocyc.)-P-N is -163° in 8, but 95° in 9. The structure determination of 10 served only to confirm the (unexpected) connectivity; the crystal quality was too poor to allow quantitative conclusions.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19941270905
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