Deoxygenation of nitro and nitroso arenes via chromium atom cocondensation
✍ Scribed by J.A. Gladysz; J.G. Fulcher; S. Togashi
- Publisher
- Elsevier Science
- Year
- 1977
- Tongue
- French
- Weight
- 221 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0040-4039
No coin nor oath required. For personal study only.
✦ Synopsis
Previous work from our laboratory has established that epoxides are deoxygenated upon cocondensation with first row transition metals Ti, V, Cr, Co, and Ni.' To date, however, we have been unable to observe oxygen abstraction from compounds containing carbon-oxygen multiple bonds,2 or any other substrate where direct removal of an oxygen atom would afford a highly reactive species. In this comnunication, we report the successful reductive deoxygenation of substrates containing nitrogen-oxygen multiple bonds. Thus generated are both stable compounds (including coupled dimers) and reactive intermediates which give rise to secondary reaction products. Compared to other metal atom-organic substrate reactions, which are generally of the oxidative addition3 or n-complex formation4 type, the transformations reported herein are mechanistically unique and expand the range of organic chemistry accessible via energy-rich5 metal atoms. All cocondensations were conducted at 77°K and < 10m4 torr in the type of metal atom reactor employed by Skell and Klabunde. 334 Chromium atoms were produced by the resistive heating of coated tungsten rods. After cocondensation, the cooling bath was removed and the matrix allowed to warm over a one hour period under static vacuum. Volatile (b.p. 2 200°) products were then pumped into a cold trap, and others were recovered by extracting the reactor residue. Product identity was established by glc, tic, nmr, and mass spectral analysis. Nitrobenzene (I, 24.4 mnol) was cocondensed with chromium (1.67 assol. corrected') to afford a green matrix. No volatile organometallic complexes were noted upon warming, but nitrosobenzene (II), azoxybenzene (III), cis and trans azobenzene (IV), and aniline (V) were --