Science of Synthesis

Williams, A. C.; Camp, N., Science of Synthesis, (2003) 14, 380.

In ‌Scheme 31‌ examples of the reactions of phenols and anisoles with 3-oxoalkanoic acid derivatives, catalyzed by phosphoric acid and its derivatives, to give 2H-1-benzopyran-2-ones ‌96‌–‌98‌ are given.[‌199‌,‌226‌–‌230‌] A difference in the regiochemistry of the cyclizations has been observed between polyphosphoric acid (as in the formation of ‌97‌) and polyphosphate ester (as in the formation of ‌98‌), the origin of which is unclear.

‌Meeeee 88‌ 8M-8-Meeeeeeeee-8-eeee ee Meeeeeee Meeeeeeee Meeeeeeee ee Meeee Meeeeeeeee Meee Meeeeeeeeee[‌888‌,‌888‌–‌888‌]

Meeeeeeeeeee Meeeeeeeee

8-Meeeeee-8-eeeeee-8M-8-eeeeeeeeee-8-eee (‌88‌, M8 = M8 = M; M8 = MMe; M8 = Me); Meeeeee Meeeeeeee:[‌888‌]

Meeee eeeeeeeeeeee (88.8 e, 888 eeee) eee eeeee eeee 88 eee, eeee eeeeeeee, ee e eeeeeee ee 8,8-eeeeeeeeeeeeeeee (M8 = M; M8 = M8 = MMe; 88 e, 888 eeee) eee eeeeeeeeeeeeee eeee (888 e) ee 88°M. Meeee eeeeeeee eee 8 e, eee eee M8M (888 eM) eeee eeeee eee eee eeeeeeeee eeeeeee eeeeeeeee eeee 8 eeeeeeee ee Me8M. Mee eeeeeeee eeeeeee eeeeeeee eeee eeeee eee eeeeeeee ee eeeee eeee eeeeeeeeeeee eee eee eeeeeeee eeeeeee ee 888–888°M/8.8 Meee eeeeeeeee eee eeeeeeeeeeeeee (MeMMe/eeeeeeeee eeeee); eeeee: 8.8 e (88%); ee 888–8°M.

8-Meeeeee-8-eeeeee-8M-eeeeeee[8,8-e]eeeee-8-eee (‌88‌):[‌888‌]

M8M8 (88 e, 88.8 eeee) eee eeeee ee eee Me8M (88 eM) ee MMMe8 (88 eM) eee eee eeeeeee eeeeee ee 88°M eee 88 e. Meee eee eeeeeeeee eeee, 88 eM eeee eeeee ee eeeeeeeeeee-8,8-eeee (8.88 e, 88 eeee) eee eeeee eeeeeeeeeeee (8.88 e, 88 eeee) eee eee eeeeeee eeeeeee ee ee eee 88 e: eee eeeeeeeeeee eee eeeeeee ee eeeeeeeeee eee eeeeeee eeee eee MeMM. Meee eeeeeee, eee eeeeeee eeeeeeeee eeee eee eeeeeeeee eeee ee eeee eeeee eeeeeeee; eeeee: 888 ee (88%); ee 888°M.

References

Meeeeee Meeeeeeeeee

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