Science of Synthesis

König, B., Science of Synthesis, (2001) 9, 208.

3-Halofurans ‌121‌ and ‌123‌ are available by a versatile route starting from 4-hydroxyalk-2-yn-1-ones ‌120‌ or their protected analogues ‌122‌ (‌Scheme 41‌).[‌213‌] On treatment with hydrochloric acid, hydrogen bromide, or hydrogen iodide, furans are obtained by addition of HX to the triple bond and subsequent acid-catalyzed cyclization of the cis-butene intermediate. Alk-3-yne-1,2-diols have been cyclized with iodine.[‌214‌]

‌Meeeee 88‌ Meeeeeeee ee 8-Meeeeeeeee[‌888‌]

Meeeee eeee eeeeeeeeeeeeeeee eeee eeeeee ‌888‌ eee eeeeeeee eeee eeeeeeee eeeeeeeee eeee eeeeee eeeeeeeee eeeeee, eeee ee ‌888‌, eee eeeeeeeee eeee eeeeee ‌888‌, eeee ee eeeeeee ee eeeeee (‌Meeeee 88‌). Mee eeeeeeee ee eeeeeeeee ee eeee(MM) eeeeeeee. Meeeee eee ee eee eeeee ee 88 ee 88%.[‌888‌]

‌Meeeee 88‌ Meeee Meeeeeeee ee Meeeeeeeeeee ee Meeeeeee Meeeeeeee eeee Meeeee Meeeeeeee Meeeee eeee Meeeee[‌888‌]

Meeee eeeeeeeee eeee eeeeeeeeeeeee ee e eeeeeee ee eeeeeeeeeeee eeeeeeeee eeeeeeeeee (eee eeee Meeeeee ‌8.8.8.8.8‌).[‌888‌–‌888‌] 8-Meeeeeeeeee ee eeeeeeee ee e eeeee eeeee eeee eeeeeeee eeeee ee eeeeeee eeeeeeeeeeee eeeeeee.[‌888‌] Mee eeeeeeeee ee eeeee eeeeeeeee eee eeee eeeeeee ee eeee eeeeee. Meeeeee, eeee ee eeeeeeee, eeeee ee eeeeeeeee ee eeeee eeeeeee eeee eeeeeeeeee, eee eee eeeeeeee eeeeeeeee eee eee eeeeeeeeeee ee 8-(eeeeeeeeeeeee)-8-eeeeeeeeeee.[‌888‌–‌888‌] Meeeeeeeeee eeeeeee eeeee 8-eeeeeeeeeee 8-(eeeeeeeeeeeee)-8-eeeeeeeeeeee.[‌888‌] Me eee eeeeeeee ee eeeeeeeeeeee eeee eee eeeeeeeee eeeeeeee ee eeeee eeeeeeeeeeee eeeeee, eeee ee eeeeeee eeeeeeee, eeeeeeeeee eeeeeeee, ee eeeeeeeeee eeeeeeeeeee, 8-(eeeeeeeeeeee)-8-eeeeeeeeeee ee eeeeeeee.[‌888‌,‌888‌]

Meeeeeee eeee ee ‌888‌ eee ee eeeeeeee ee eeeee eeeeeeeee ee eeeeee 8,8-eeeeeeeeee eeeeeeeee. Mee eeeeeeeeeee ee eeee eeeeeeeee ee eeeeee ‌888‌ eee ee eeeeeeeeeeee ee eeeee, Meeee eeeee,[‌888‌–‌888‌] ee eeeee (‌Meeeee 88‌).[‌888‌,‌888‌] Meeeeeee eeee eeee eeeeeeeee eeeeeeeeeeeeeeeee.[‌888‌]

‌Meeeee 88‌ Meeeeeeee ee Meeeee eeee Meeeeeee[‌888‌–‌888‌]

Mee eeeeeeee ee eeeeeeee eeeeeee ‌888‌ ee γ-eeeeeeeeeeeeeeeee ‌888‌ eeeeeeeee ee eeeeeeeee eeeeeeee ee eeeee ee eee eeeeeeeee ee 8,8-eeeeeeeeeeeee eeeeee.[‌888‌] Mee eeeeeee eeeee ee eeeeeeeee eeee ee eeeeee, eeee(8,8-eeeeeeeeeeeeeee)eeeeeeeee (MMMMM), ee eeeeeeee ee eeee eeeeeeeee: eeee 8 eee% ee eeee eee eeeeeeee eeeeee eeeeee eeeeeeeeeee ‌888‌ (‌Meeeee 88‌, eeee e), eeeeeee 8 eee% ee eeeeeeeee eeeeeeee eee 8 eee% ee eeee(8,8-eeeeeeeeeeeeeee)eeeeeeeee eeeeee ee ee 88% ee eeeeeeeeeeeee eeeee ‌888‌ (‌Meeeee 88‌, eeee e).

‌Meeeee 88‌ Meeeeeeee-Meeeeeeee Meeeeeeee ee 8,8-Meeeeeeeeeeee Meeeee[‌888‌]

Meeeeeeeeeee Meeeeeeee

8-Meeee-8-eeeeeeeeeee (‌888‌, M8 = M; M8 = Me; M = Me); Meeeeee Meeeeeeee:[‌888‌]

M eeee ee 8-eeeeeee-8-eeeeeeeee-8-ee-8-eee (888 ee, 8.8 eeee) eee 8 M MMe (8.8 eM) ee eeeeeee (8 eM) eee eeeeee ee 88°M eee 8 e. Meeee eeeeeee ee ee, eee eeeeeee eee eeeeeee eeee Me8M ee MeMMe (88 eM) eee eeeeee eeee eee (88 e). Mee eeeeeee eeeee eee eeeeeeeee eeee Me8M, eee eee eeeeeeee eeeeeee eeeeee eeee eeeeee eeee ee MeMMM8 eeee, eeeee, eee eee eeeeeee eee eeeeeeeeee. Mee eeeee eeeeeee eee eeeeeeeeeeeeeee (eeeeee eee, Me8M/eeeeee 8:8) ee eeee 8-eeeee-8-eeeeeeeeeee; eeeee: 888 ee (88%); ee 88–88°M.

Meeeee 8-(8-Meeee-8-eeeee)eeeeeeeee [‌888‌, M8 = (MM8)8Me; M8 = M8 = M; M8 = (MM8)8MM8Me];
Meeeeee Meeeeeeee:[‌888‌]

M eeee ee eeeeee 8-[8-(8-eeeeeeee)eeeeee-8-ee]eeeeeeeee (8.88 e, 8.8 eeee) eee e eeeee eeeeee ee MMe ee MMMe8 (88 eM) eee eeeeeeee eee 8 e. Mee eeeeeee eee eeeeeee ee eeee ee ee, eeeeeee eeee M8M, eee eeeeeeeee eeee MMMe8. Mee eeeeeeee eeeeeee eeeeee eeee eeeeee eeee ee MeMMM8 eee MeMe eeeee, eeeee (MeMM8), eee eee eeeeeee eee eeeeeee. Mee eeeeeee eee eeeeeeeee ee eeee eeeeee 8-(8-eeeee-8-eeeee)eeeeeeeee; eeeee: 8.88 e (88%); ee 888°M (88 Me).

8-(Meeeeeeeeeeee)-8-eeeeeeeeeee:[‌888‌]

M eeeeeee ee M-eeeeeeee (8.8 e, 88 eeee) eee eee, eeeeeeeeeee MMM (8.8 e, 88 eeee) eee eeeeee ee 888°M eee 88 eee. M8M (88 eM) eee eeeee eee eee eeee eee eeeeeeeeeeee eeeeeeeee eeee MeMMe. Mee eeeeeee eeeee eee eeeee (MeMM8) eee eee eeeeeee eee eeeeeeeee eee. Mee eeeeeee eeeeeeee eee eeeeeeee eeeeeee e eeeee eeeeee (eeeeee eee, MeMMe/eeeeeeeee eeeee 8:8) ee eeee 8-(eeeeeeeeeeeee)-8-eeeeeeeeeee ee ee eee; eeeee: 8.8–8.8 e (88–88%); ee 88–88°M/8.8 Me. Mee eeeeeeee eeeeee eeeeeeeeee ee eeeee; ee 88–88°M.

References

Meeeeee Meeeeeeeeee

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