Science of Synthesis

König, B., Science of Synthesis, (2001) 9, 249.

Electrophilic halogenation of furan under the usual conditions for arenes is rarely successful. The acid-sensitive heterocycle decomposes via ring opening or polymerization reactions.[‌560‌] Furans bearing electron-withdrawing substituents are more stable towards acids, but less reactive in electrophilic substitution reactions. However, in general they are more suitable for halogenation reactions. Several methods have been developed for the synthesis of halofurans that avoid direct halogenation: decarboxylation of salts of furoic acids (Hunsdiecker reaction), reaction of furyllithiums with sources of halogens, and reaction of mercuriofurans with halogens.

Mee eeeeeeeeeee ee eeeeeeeeeeee eee eeeeeeee ee eeeeeeeeeeeeeeeeeeeee.[‌888‌] Me eeee eeeeee, 8-eeeee-8-eeeeee eeee (‌888‌) eee eeeeeee eeee Meeeeeeeeee eeeeeee (‌888‌) ee eeeeeee 8-eeeee-8-eeeeeeeeeee (‌888‌). Meeeeee–eeeeeee eeeeeeee eee eeeeeeee ee eee eeeeeeeeeeeeeeeeee eee ee eee eeeeeeee, eee eeeeeeee, eeeeeeeeeee ‌888‌. M eeeeee eeeeeeeee eeeeeee eeeeeeee 8-eeeeeee-8-eeeeeeeeeee (‌888‌) ee 88% eeeeeee eeeee (‌Meeeee 888‌).

‌Meeeee 888‌ Meeeeeeee ee Meeeeeeeeeee ee Meeeeeeeeeeeeeeeeeeee[‌888‌]

Mee eeeeeeeee ee 8-eeeeeeeeeee (‌888‌) ee eeeeee eeeeeeeeeeee[‌888‌,‌888‌] eee eeee eeeeeeeee ee e eeeeee.[‌888‌] Meeeeeeee eeeeeee ee e eeeeeeeeee eeeee eee eeeeeeee ee 8-eeeeeeeeeeee (‌8‌) eeee eeeeeeeeeeeeeeee[‌888‌] (eee Meeeeee ‌8.8.8.8.88‌) ee eeeeeeeeeeeeeee ee eeeeeeeeeeee eeeee (‌Meeeee 888‌).

‌Meeeee 888‌ 8-Meeeeeeeeee eeee 8-Meeeeeeeeeee[‌888‌]

Mee eeeeeeee ee eeeee (‌8‌) eeee eee ee eee eeeeeeeeeee ee eeeeeee ee eeeeeeeeeeeeeeeee eeeee eeeeeeeee eeeeeeeeee eeeeeeeeee eeeeee eee eeeeeeeee ee 8-eeeee- (‌888‌) eee 8,8-eeeeeeeeeeee (‌888‌) ee e eeeee eeeee (‌Meeeee 888‌).[‌888‌] Meeeeeee-eeeeeeeeeee eeeeee, eeee ee 8-eeeeee eeee ee 8-eeeeeeeeeee, eee ee eeeeeeeeee eeee eeeeeee ee 8,8-eeeeeeeeeeeeee ee eeeeeeee ee eeee eeeeee, eee eeeeee eeeeeeeee eeeeeeee ee M8 ee eeeeeeee (‌Meeeee 8‌).[‌888‌] Me eee eeeeeeeeeee ee eeeeeee eee eeee ee eee eeeeeeee ee 8-eeeeeeeeeee, ee 88% eeeee ee 8,8-eeeeeee-8-eeeeeeeeeee ee eeeeeeee.[‌888‌] Meeee eeeeeeeeeeeeeeee eeeeeee eeeeeeeeeeee ee eeeee ee eee α-eeeeeeeee,[‌888‌] eee eeeeeeee ee eee eeeeeeeeeee ee eeeeeeee eeeeeeeeeee eeeeee eeeeeeeeeee ee M8.[‌888‌–‌888‌] Me eeee eeeee M-eeeeeeeeeeeeeeee eee eeee eeee eee eeeeeeeeeeee.[‌888‌–‌888‌] M eeeeeeeee eeeeeeeee ee 8,8-eeeeeeeeeeee (‌888‌) eeee eee eeeeeeeeeeeeeee ee eee eeeeee eeee ee 8-eeeee-8-eeeeee eeee (‌888‌) ee eee eeeeeeee ee eeeeeee eee eeeeeeeee eeeeeee (‌Meeeee 888‌).[‌888‌] Meeeeeeeeeeeeee ee 8,8-eeeeeee-8-eeeeee eeee eeeee 8,8-eeeeeeeeeeee,[‌888‌] eeeee eee ee eeeeeeeeeee ee eee eeeeeeeeeeeee eeeeeeee 8-eeeeeeeeee ee eeeeeee–eeeeeee eeeeeeee ee M8 eee eeeeeeeee ee eee eeeeeeeeeeee eeee eeeee.[‌888‌] Meeeeee eeeeeeeee eeeeee eee eee eeeeeeeee ee 8-eeeeeeeeee ee eeeeeee eeeeeeee ee eee Meeee–Meeee eeeeee ee eeeeee eeeeeeeee eee eeeee eeeeeeee ee eeeee-Meeee–Meeee eeeeeeee eee eeeeeeeeeee ee eeeeeeee eeeeeee ee eeeeeeeee ee 888°M.[‌888‌]

Meeeeeeeee eeeeee ee eeeeeeee ee e eeeeeeeee eeeeee ee eeeeee eeeeeeeeee.[‌888‌] Mee eeeeeeee ee eeeeeeeeeeeeee ‌888‌, ‌888‌, ee ‌888‌, eeeeeeee eeee ‌8‌ ee ‌888‌, eeee eeeeee eeeeee eee eeeeeeeee ee eeeeeee eeeeeeeeeeee ‌888‌, ‌888‌, eee ‌888‌ (‌Meeeee 888‌).[‌888‌–‌888‌] Meeeeeeeeeeeeee ee 8-eeee-8-eeeeee eeee ee eee eeeeeeee ee eeeeee eee eeeeeeeee eeeeee eeeeee 8,8-eeeeeeeeeee, ee e eeeeee eeeeeee ee eeee eeeeeeeee eeeee eee eee eeeeeee eeeeeeeeee.[‌888‌] Meeeeeee ee eeeeeeeeeeeee eeee eeeeee ee eeeeeee eeeeee eee eee eeeeeeeeeee ee eeeeeeeeee.[‌888‌]

‌Meeeee 888‌ Meeeeeeeeee ee Meeeee[‌888‌]

‌Meeeee 888‌ Meeeeeeeeeee ee e Meeee Meeeeeeeeee ee Meeeeeeeeeeeeee ee eee Meeeeeee ee Meeeeee eee Meeeeeeee Meeeeee[‌888‌]

‌Meeee 8‌ Meeeeeeeeee ee Meeeee

Meeeeeee Meeeeeee	Meeeeee	Meeeeee	Meeee (%)	Mee
	MMM (8 eeeee)		88	[‌888‌]
	MMM (8 eeeee)		88	[‌888‌]
	MMM (8 eeeee)		88	[‌888‌]
	Me8, 8,8-eeeeeeeeeeeeee		88	[‌888‌]
	Me8, Me8M8		88	[‌888‌]
	Me8, MeMe8		88	[‌888‌]
	Me8, MeMe8		88	[‌888‌]

Meeeeeeeeeee Meeeeeeee

‌Meeeee 888‌ Meeeeeeee ee Meeeeeeeee eeee Meeeeeeeeeeeee[‌888‌–‌888‌]

8-Meeeeeeeee (‌888‌):[‌888‌]

Me8 (888.8 e, 8 eee) eee eeeee ee MMM (888 eM) eeeeee ee −88°M. Mee eeeeeeeeeee eeeeee eeeeeeee eee eee eeeeee +88°M. Mee eeeee eeee eee eeeeeeeeeee eeee e eeeeeeee eeeeee eee eee eeeee eeeeeeee ee e eeee ee eeeeeee eeeeeeeee eeeee (888 e, 8.8 eee) ee MMM (888 eM). Mee eeeeeeeeeee ee eee eeeeeee eee eeeeeeeeee ee eeeeeeee eeeeeee ee eeeeeee 88 eee 88°M. Meeee eeeeeeee eeeeeeee eee eeee eee eeeeeee ee 88–88°M eee 8.8 e eee eee eeee eeeeee eeee eee eeeee (8 M). Meeee 8 eee ee eeeeeeeee eeeeee eee eeeeeee eeeee eee eeeeeeeee, eee eeeeeee eeeee eeeeeeeee eeeeeeeeeeee eeee eeee eeeeeee eeeeeeeee eeeee (88, 88, eee 88 eM), eee eee eeeeeeee eeeeeee eeeeee eeee eeeeee eeeee eeee eee eeeee (eee eeeeeee eeeee ee eee eeeee eeeee), eee eeeee (MeMM8). Me8MM (e eee eM) eee eeeee ee eeeeeeeeee eeeeee ee eeee eee eee eeeee eeee eee eeeeeeeeeee ee e 8 M eeeee eee eeeeeeeee ee eeeee eeee e Meeeeee eeeeee (88 ee) eeee e eeeeeeeee eeeee eeeeee ee −88°M. Mee eeeeee eeeeeeee eee eeeee (MeMM8) eee, eeeee eeeeeeee ee Me8MM (8 e), eeeeeeeee eeeeeeeee eeee e Meeeeee eeeeee (88 ee). Mee eeeeeeee eeee ee 88–888°M eee eeeeeeeeeee ee eeee eeee 8-eeeeeeeeee; eeeee: 888.8–888.8 e (88–88%); ee 888°M/88.8 Me.

8,8-Meeeeeeeeeee (‌888‌):[‌888‌]

Meeee eee eeee eeeeeeeeee ee eeeeeeeee eee 8-eeeeeeeeee, Me8 (88.8 e, 8.8 eee) ee MMM (888 eM) eee eeeee ee eeeee (88 e, 8.88 eee) ee MMM (888 eM) eeee 8 e ee 88–88°M. Meeee eeeeeeee eeeeeeee eee eeeeeee eee eeeeee ee 88°M eee 88 eee, eeeeee eeee eee eeeee (8 M), eeee eeeeee eeee eeeeeeeeeee eeeee eee 8 eee eee eee eeeeeee eeeee eee eeeeeeeee eeee eeeeeeeee eeeee (888, 88, eee 88 eM). Mee eeeeeeee eeeeeee eeeeee eeee eeeee (MeMM8), eeeeeeeeeeee ee eeeee, Me8MM (8 eM) eee eeeee, eee eee eeeeeee eee eeeeeeeee eeeeeeeee eee e Meeeeee eeeeee (88 ee) ee eeee 8,8-eeeeeeeeeeee; eeeee: 88.8 e (88%); ee 8–8°M; ee 88°M/8.8 eMe.

8,8-Meeeeeeeeeee (‌888‌):[‌888‌]

Me e eeee ee 8-eeeee-8-eeeeee eeee (88.8 e, 88.8 eeee) eee MeMM (8.8 e, 88.8 eeee) ee M8M (88 eM) eee eeeee eeeeeeee e eeee ee Me8 (8.88 e, 88.8 eeee) eee MMe (8.88 e, 88 eeee) ee M8M (88.8 eM). Mee eeeeeee eee eeeeee ee eeeeee eee 8,8-eeeeeeeeeeee eee eeeeeeeee eee eee eeeeee eeee 8% ee Me8M8M8 eeee eee M8M ee eeee 8,8-eeeeeeeeeeee; eeeee: 8.88 e (88%); ee 8–8°M; ee 88–88°M/8.8 eMe.

References

Meeeeee Meeeeeeeeee

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