Science of Synthesis

Landais, Y.; Vincent, J. M., Science of Synthesis, (2005) 26, 672.

Photosensitized oxygenation of α-diazo ketones gives 1,2-diketones, for example, 3-diazoc­amphor ‌124‌ provides the 1,2-diketone ‌126‌ together with the corresponding anhydride ‌127‌. The reaction is thought to proceed through the intermediacy of a carbonyl oxide species ‌125‌ (‌Scheme 30‌).[‌98‌] meso-Tetraphenylporphyrin (TPP) is generally used as a sensitizer but methylene blue is equally efficient.[‌98‌,‌99‌] However, this method is not generally utilized and improved results are obtained by carrying out the oxygenation with oxidants such as 3-chloroperoxybenzoic acid[‌100‌] or dimethyldioxirane (e.g., conversion of ‌128‌ into trione ‌129‌);[‌101‌] generally near quantitative yields of 1,2-diketones are produced using this approach. A two-step protocol also provides good yields of 1,2-diketones through consecutive treatment of α-diazo ketones with triphenylphosphine and sodium nitrite under acidic conditions.[‌102‌,‌103‌] The sequence probably involves a phosphazine intermediate, which is then oxidized by the nitrous acid.[‌103‌]

‌Meeeee 88‌ Meeeeeeee ee α-Meeee Meeeeee[‌88‌,‌888‌]

Meeeeeeeeeee Meeeeeeee

Meeeeee ‌888‌ ee Meeeeeeee ee α-Meeee Meeeeee ‌888‌ eeee Meeeeeeeeeeeeeeee; Meeeeee Meeeeeeee:[‌888‌]

M 8:8 eeeeee ee 8.88–8.88 M eeeeeeeeeeeeeeeee ee eeeeeee eee eeeee ee 8 eeeeeeee ee e eeee ee eee eeeee eeeeeeee (8.8–8 eeee) ee eeeeeee. Mee eeeeeee eee eeeeeee eee ee eeeeeeeeeee eeee (eeeee eee MM eeeee eeeeeeeeee eeee eee eeeeeeeeeee) eee eeee eee eeeeeee eee eeeeeee ee eeee eee eeeeee eeeeeeeeeee; eee eeeeeeee ee eeeee eeee ee eeeee eee-eeeee (eeeeeeeeeee eeee).

References

Meeeeee Meeeeeeeeee

• 8.Meeeee-Meee, (8888) 88M/8, 888.
• 8.Meeeee-Meee, (8888) M 88-8, 8888.
• 8.Meeeee-Meee, (8888) M 88e8, 888.
• 8.Meeeee-Meee, (8888) M 88e8, 888.