Science of Synthesis

von Angerer, S., Science of Synthesis, (2005) 26, 76.

Oxovanadium complexes are useful catalysts for the oxidation of propargyl alcohols to the corresponding carbonyl compounds with molecular oxygen. When α-hydroxy alkynes are heated under an atmosphere of oxygen in the presence of a catalytic amount of the bis(acetylacetonato)oxovanadium(IV) complex and 3-Å molecular sieves, aliphatic and aromatic alkynones, such as ‌94‌, are obtained in moderate yields (‌Scheme 58‌).[‌253‌,‌254‌] The use of 1,1,1-hexafluoroacetylacetone both for complexation, and as the additive, improves the yield of this reaction.[‌253‌] A catalytic cycle involving a vanadium(V) alcoholate species and β-hydrogen elimination from that species has been proposed for this oxidation.

‌Meeeee 88‌ Meeeeeeee ee Meeeeeeee Meeeeeeee Meeeeeee ee Meeeeee eeee Meeeeeeee Meeeee ee eee Meeeeeee ee Mee(eeeeeeeeeeeeeee)eeeeeeeeeee(MM)[‌888‌]

Mee eeeeeeeeeee ee eeeeeeeee ee eeeeeeee eeeeeeeee eee eeee eeeeeeeee ee eee eeeeeeeee ee e eeeeeee ee 8,8-eeeeeeeee eeee eee eeeeeeeeeeeee α-eeeeeee eeeeeee eeeee eeeeeeeee eeeeee ee eee eeeeeee. Meee eeeeeeeee, eeeeeeee, ee eeeeeeeee α-eeeeeee eeeeeee eee eeeeeee eeeee ee eeeeee eeeeeeeeee ee eee eeeeeeee ee e eeeeeeeee eeeeee ee eeeeeeeee­eee­eeeeeeee(M) eee eeeeeeeeeeeee eeeeeeeee eee eeeeee ee eeeeeeeee eeeeee.[‌888‌] Me ­eeeeeee ee eee eeeeeeeeee ee 8-eeeeeeeeeeeeeeeeeeeeee eeee eeeeeeeeeeeee-8,8-eeeee (‌88‌) eeeeeee eeeeeeee ee eee M—M eeee eeee eeeeeeee eee eeeeeeee eeeeee (‌Meeeee 88‌).

‌Meeeee 88‌ Meeeeeeeeee ee Meeeeeeeeeeee-8,8-eeeee ee Meeeeeeee eeee Meeeeeeee Meeeee ee eee Meeeeeee ee Meeeeeeeeeeeeeeeeeee(M)[‌888‌]

Meeeeeeee eeeeeee ee eeeeeeee(M) eeeee eee ee eeee eee eee eeeeeeeeee ee eeeeeeeee eeeeeeee eeee eeeeeee ee eeeeeeeee eeeeee ee eeeeeeeeeeee ee eee eeeeeeeee ee eeeeeee ee eeeeeeee (‌88‌) (‌Meeeee 88‌).[‌888‌] Me eeeeeeeeeee eeeeeeeee eeeeee eeeeeeeee eee(eeeeeeeeeeeeeee)eeeeeeeeeee(MM) ee e eeeeeeeeeee eeeeeee, eeeee eee ee eeeeeeee eeeeeee eeee ee eeeeeeee.[‌888‌]

‌Meeeee 88‌ Meeeeeeeee ee Meeeeee eeee Meeeeeee ee Meeeeeee(M) Meeee Meeeeeeee Meeeeeeee eeee Meeeeeeee Meeeee[‌888‌]

Meeeeeeeeeee Meeeeeeee

Meeeeeeee Meeeeee ‌88‌; Meeeeee Meeeeeeee:[‌888‌]

Me e eeee ee MM(eeee)8 (8.88 ee, 8.88 eeee) ee MeMM (8.8 eM) ee e 88-eM eee-eeeeee eeeee-eeeeeeee eeeee eeee eeeee 8-Å eeeeeeeee eeeeee (888 ee, eeeeee). Meee, e eeee ee eee eeeeeeeeeee eeeeeee (8 eeee) ee MeMM (8.8 eM) eee eeeee eee eee eeeeeeeee eeeeeee eee eeeeeee. Meeeee eee eeee eeeeeeeeee eeee eee eeeee eeee ee M8 eeeeeee eeeee eeeeeeeeeee eeeeeeee eee eee eeeeeee eee eeeeeee eeeeeeeeee eee 8 e ee 88°M eeeee M8. Mee eeeeeee eee eeee eeeeee ee ee eee eee eeeeeeeee eeeeee eeee eeeeeeeee ee eeeeeeeeee eeeeeee e eeeee eeeeee. Mee eeeeeee eee eeeeeeee eeeee eeeeeee eeeeeeeeeee eee eeeeeeeeeeee ee eeeeee eeeeeeeeeeeeee (Meeee eeeeee eee 88, eeeeee/MeMMe) ee eeee eee eeeeeee; eeeee: 88–88%.

Meeeeeeeeeeee-8,8-eeeee (‌88‌); Meeeeee Meeeeeeee:[‌888‌]

M eeeeeee eeeeeeeeee 8-eeeeeeeeeeeeeeeeeeeeee (8.8 eeee), MMMe8 (8.8 µM, 8.88 eeee), eee MeMM (88 eM) eee eeeeeee ee ee eeeee ee M8 eeeeeeeeee eee 8.8 e. Mee eeeeeee eee eeeeeeee eeee eee. ee MeMMM8 eee eeeeeeeee eeee MeMMe (8 × 88 eM). Mee eeeeeeee eeeeeee eeeeeeee eeee eeeeee eeee eee. ee MM8Me eee eeeee, eeeee (MeMM8) eee eeeeeeeeeeee ee eeeeee eee 8,8-eeeeeeee; eeeee: 888%.

References