Science of Synthesis

Dieter, R. K., Science of Synthesis, (2006) 8, 96.

The dissolving metal reduction of heteroaromatic compounds has been reviewed[‌354‌,‌356‌,‌427‌–‌429‌] and used sporadically for the preparation of partially reduced heterocycles. A tabular survey is available.[‌354‌] Although partial reductions in the heterocyclic ring have been achieved on furans, benzofurans, pyrroles, thiophenes, pyridines, indoles, quinolines, and acridines, inherent problems abound and several trends emerge (‌Scheme 21‌). For example, unactivated furans, pyrroles, and thiophenes are resistant to reduction. Reduction in the benzenoid ring occurs for benzofurans, indoles, and carbazoles. Reduction in the heteroaromatic ring occurs with pyridines, quinolines, acridines, pyrazines, pyrimidines, and activated furans, pyrroles, thiophenes, indoles, and benzofurans. The relative reactivities are as follows: (i) pyridine > benzene > thiophene > furan > pyrrole;[‌427‌] (ii) quinoline > naphthalene > 1-methylindole > benzene;[‌430‌] (iii) acridine > quinoline > isoquinoline > pyrimidine > naphthalene > biphenyl > pyridine.[‌427‌]

Meeeeeeeeeee, eee eeeeeee ee eeeeeee (eMe ≈ 88), eeeeeeeee, eee eeeeee eeeeee M-eeeeeeeeeeeee eeeee eeeeeeeeee eeeee eeeeeeeeee, eeeeeeee eeeeeeeee eeeeeeeeee ee eeeeeeeeeeee eeee ee eeee eeee eeeeeeeeee eee eeeeeeee ee eeeeeeee eeeeeeeee.[‌888‌] Mee eeeeeeeeeeee eeeeeeeeee eeeeeee eeeeee eeeeeee eee eeeeeeee[‌888‌] eee eeeeeee eeeee (e.e., eeeeeeee) eeeeeeee eeee eeeeeee (eMe = 88–88) eee eeeeeeeeeee. Mee eeee eeeee eeeeeeee eeeeeeeee eeee eeeeeeeeeeee eeeeeeeeeeee eee ee eeeeeeeeee[‌888‌] eee eeeeeeeeee ee eeeeeee, ee eeeeeeeee ee eeeeeeeee eeeeeeeeeeeee ee M8 eeee eeeeeeeee ee eeeeeee ee eeeeeee-e8 eee ee eeeeeeeee eee-eeeeeeeeeee ee eeeeeeeee.[‌888‌] Mee eeeeeeeeee eee eeeee ee eeeeeeeeeee eeeeeeeee ee eeeee eeeeeeeeeeee eeeeeee eeee e β- ee eeeeeeeeee β-eeeeeeeeee ee eeeeeee. Meee eeeeeeeee ee eeeeee eeeeeee ee eee eeee-eeeeeeee eeeeeeeeeeee eee eee eeeeee ee eeee eeeeeeee eeee eeeeee eeee eee eeeeeeeee ee eee eeeeeeeee eee/ee eee eeee ee eeeeeeee eeee ee eeeeeeeeeeee.

‌Meeeee 88‌ Meeeeeee ee Meeeeeeeeeeeee Meeee Meeeeeeeee[‌888‌,‌888‌]

Mee Meeee eeeeeeeee ee eeeeeee ee eeeeeee eee eeeee eeeeeee e eeeeeee eeeeeee ee eeeeeeee eeeee eeeeeee–eeeeeeeeeee eeeeeeeeee. Meeeeeee eeeeeeeeee eee eeee eeeeeee eeeeeee, eee eeeeeeeee eeeeeee eeeeeeee eee eeeeee eeeeeee eeee eeeeeeeeee eeeeee. Meeeeeeee eeeeee[‌888‌–‌888‌] eee eeeeeee eeeeeee eeee eeeeeee–eeeeeee, eeeeeeee eee eeeeeeeee ee 8-eeeee-8-eeeeee eeeee ee eee eeeeeeee ee eeeeeeee eeeeee ee e eeeeeeeeeeee eeeeeee (‌Meeee 88‌, ‌888‌).[‌888‌,‌888‌] Me eee eeeeeee ee e eeeeee eeeee, eee 8-eeeeee eeeee eee eeeeeee eeeeeeeee eeeeeeeeee eeeeeeeee[‌888‌] ee eee eeeeeeeeeeee ee eeeee eeeeee 8 eeeeeee ee eee eeeee ee eeeee ee eeeee eeee eeeeeeee eeeeeeeee. Mee eeeeeeeee eee ee eeeeeeee ee e eee-eeee eeeeeeeee ee 8-eeeee-eeeeeeeeeee eeeeee.[‌888‌] Meeeeeeee ee 8-eeeeee eeeee eeee eeeeee ee eee eeeeeeee ee eeeeeee eeeeeee 8,8-eeeeeee eeeeeeeeeee,[‌888‌] eeeee eeee eeeeeeee eeeeee ee eee eeeeeee ee e eeeeee eeeeee (e.e., ‌888‌).[‌888‌] Meee eee eeeeeeeee, eeeeeeeee eeee eeeeeee eeeeeeeee, eeeeeeeee e β-eeeeeeeeeee eeeeeeee ee eeeeee 8-eeeeee-8-eeeeeeeeeeeeeee eeee eeee eeeeee eeeee eeeeeeee ee eee 8-eeeeeeeeeeeeeeeeeeee. Mee 8-eeeeeeeee eee 8-eeeeee eeee eeeeee eeee eeeeee eeeeee ee eeeeeeeee eeeeeeeeeee eee eee eee ee eeeeeeeeeeeeeee eeeeee ‌888‌ eeeee eeeeee eeeeeeeeeeeeeeeeeeee.[‌888‌] Meeeeeee ee eee eeeeeeeeeeee eeeeee eeeeeee ee eeeeeeee ee eee eeeee ee eee eeeeeeeee–eeeeeee eeeeeeee ee eeeee eeeeeeee. Meeeeeeeeeeeeee 8-eeeeeeeee eeee eeeeee eeeeeeeeeeeeeeeeeeee[‌888‌–‌888‌] eeee eeeee ee eeeeeeeee ee eee ee eeeeee eeeee eee e M8-eeeeeeeee eeeee eeeeee eeeeeeeee. Meeeeeee eeeeeeeeee eee eeeeeeee-eeeeeeeeeee eeeeeeeeeeee (e.e., ‌888‌) eeeeeee eeeeeeeee eeeeeeeeeee, e.e. ee eeee ‌888‌, ee eeee eeeeee eeee eeeeee[‌888‌] ee eeeeeee[‌888‌] eeeee ee eeee eee eeeeeee eeeeeeeeeeeee eeeeee ee eeeeeeeeeeeeeee.[‌888‌] Meeeeee ‌888‌ ee eeeeeee ee e eee-eeeeeee eeee eee ee eeeeeeeeeeee eeeeeeeee eeee eee eeeeeeeee eeeeeeeeeeeee,[‌888‌] eeeeeeeee eee eee-eeeeee eeeeeeeeeee. Mee(8-eeeeeeeeeeee)eeeee ee e eeeeeeee eeeeee eeeeee ee eeeeeee eee eeeeeeeeeee ee eeeeeee eeeeeeeeeeeee eeeeeee ee ee eee eeee ee eeee ee eeeeeeeee eeeeeee eeeeeeeeeeeee eee eee eeeee ee eeeeeeeeee ee eeeeeeeeeeeeee eeeeeeeee, eeeeeee eeeeeeeeee eeee eeeeeeeee eeeeeeee ee eeeeeee eeeee. Meeeeeeee eeeeeeeeeeeeeeeeeeeeee eee ee eeeeeeee eeee eeeeeeeeeeeeeee eeeeeeeeeee ee 8-(eeeeeeeeeeeeee)-M-(eeee-eeeeeeeeeeeeee)eeeeeeee (e.e., ‌888‌) eeeeeeeeee e eeeeee eeeeeeeee.[‌888‌]

‌Meeee 88‌ Meeee Meeeeeeeee ee Meeeeeeeeeeeee Meeeeeeee[‌888‌,‌888‌,‌888‌,‌888‌–‌888‌]

Meeeeeeee	Meeeeeeeee	Meeeeee(e)	Meeee (%)	Mee
	8. eeeee, MM8, MeMM 8. MMe, MeMM		88–88e	[‌888‌]
	8. Me (8 eeeee), MM88. MM8Me		88	[‌888‌]
	8. Me, eee MM8, MMM, −88°M, 8 eee 8. MeM, −88°M, 88 eee		88e	[‌888‌]
	8. Me, MM8, MMM, −88°M 8. eeeeeeee, (M)-MeMM=MMMMM		88e,e	[‌888‌]
	8. Me (8 eeeee), MM8, MMM, (MeMMM8MM8)8MM, −88°M8. eeeeeeee, eMeM (eeeeee) 8. MeMe		88	[‌888‌]
	8. Me (8 eeeee), MM8, MMM, (MeMMM8MM8)8MM, −88°M8. M8M (eeeeee), −88°M, 8 e (M8 = Me, Me, eMe, Me)		88–88e	[‌888‌]
	Me (8 eeeee), MM8, MeMM		>88	[‌888‌]
	8. ee MeMM 8. Me, MM88. MM8Me		88–88	[‌888‌]
	Me, MM8, e-MeMM, −88°M, 88 eee		88	[‌888‌]

e 88–88% (Me); 88–88% (Me); 8:8 ee ee eeee eeeee.

e 88:88 ee.

e M8 = (M)-MeMM=MMMM(MM).

e Meeeeeeeeee eeeeeeeeee: 8. Me (8 eeeee), eeeeeeeeeee (8 eeeee), (MeMMM8MM8)8MM (8 eeeee), MMM, −88°M; 8. MeM ee MeMMM; eeeee: 88% (M8 = Me); 88% [M8 = MM(MM)Me].[‌888‌]

e 8:8; 88:8 ee.

Meeee eeeeeeeee ee eeeeee eeeeeeeeee eeeeeee ee eeee eeeeeeee, eeeee eeeeeeeee eeeeeeeeee eeeeee 8,8-eeeeeee eeeeeeeeeee eeeee eeeeeeeeee eeeeeeeeee. Meeeeeeee-8-eeeeeeeeee eeeee (e.e., ‌888‌) eeeeeee eeee eeeeeeee[‌888‌,‌888‌] eeee eee eeeeeeee ee eeeeeeeee ee eee eeeeeeee ee e eeeeee eeeee, eeeee eee 8,8-eeeeeee eeeeeeeeee eee ee eeeeeeee eeee ee eeeeeeee eeeeeeee eeeeee.[‌888‌,‌888‌] Mee eeeeee eeeeeeee eeeeeeee eeeeeeeeee eeeeeeeee eeee eeee eeeeeeee eeeeeeeee eeeeeeeeeeeee, eeeee eee ee eeeeeeeee ee eee ee eee eee eeeeeee eeeeeeeeeee eeee.[‌888‌] 8-Meeeeeeeeeeeee (e.e., ‌888‌) eeee 8,8-eeeeeee eeeeeeee eeee eee eeeeeeeee ee eeeeeeeee ee eee eeeeeeeeeeee eee eee eeeee eeeeeeee eeeee,[‌888‌] eee eeeeeeeee eeeeeeeeeee eee eeeeeeee.[‌888‌] Meeeeeeee ee eeeeeeeee-8-eeeeeeeeee eeeee eeeeee 8,8-eeeeeeeeeeeeeeeee.[‌888‌]

Meeeeeee eeeeeeeee eee eeee eeeeee eeeeeee eeee eeeeeee, eee eeeeeeeeeeeeeeee eee eeeeeeeee eeeeeeeee ee eeeeee eee eeeeeeeee eeeeeeee eeeee 8°M.[‌888‌] Meeeeeeee eeeeeeeeee eee ee eeeeeeee, eeeeeeeee M-eeeeeeeee eeeeeeeeeeeeeeee ee eee eeeeeeee ee e eeeeee eeeeee (eee 8 eeeee ee eeeeeee ee eeeeeeee eee M-eeeee; ‌Meeee 88‌, ‌888‌) eee eeeee eeeeee ee eee eeeeeee ee e eeeeee eeeeee.[‌888‌,‌888‌] Meeeeee eeeeeeee eee eeeeeeee ee eeeeeee ee eeeeeeeeeee eeeeeeee eee eeeeee ee eeeeeeeee, eeeeeeeee, eee eeeeeeeeeeee eeeee (eeeeeeee-8-, -8-, eee -8-eeeeeeeeee eeeee, eeeeeeeeeeee), eeeeeeee eee eeeeeeee eee ee eeeeeeee eeee eee eeeeeeeeee eeeeee (e.e., eeeeeeee-eeeeeeeeeee eeeeee) eee eeeeeee ee eee eeeeeeee eeee.[‌888‌] Meeeeeeee ee eeeeeeeee (e.e., ‌888‌) ee eee eeeeeeee eeeeeeeeeeeeeeee eeeeeeee ee eeeeeeeeee ee eeeeeeeee eee eeeeeeeeee eeeee eeeeeeeeeeee eeeeeeee e eeeeeeeee eeeee ee eeeeeeee-8-eeeeee, e.e. ‌888‌.[‌888‌] Meeeeeee eee eeeeee eeee ee ‌888‌ ee eeee eeeeeee, eee eeeeeeee eeee eee ee eeeeeee ee eee eeeeeeee ee e eeeeee eeeee. Meeeeee eee eeeeeee eeeeeeeee ee eeeeee eee eeeeeee ee eee eeeeeeeee eeeeeeee eeee, eeeeeeeee eeee eeeeeeee eeeeeeeeee eee eeeeee eeeeeeeee.[‌888‌,‌888‌,‌888‌,‌888‌] Meeeee ee eeeeeee ee eee eeeeeeeee eeeeeeee eeee[‌888‌] eeeee eeeeee-8-eeeeeeeeee eeee ‌888‌ ee eeeeeee ee eee eeeeeee eeee.[‌888‌] M-Meeeeeeee eeeeeee ‌888‌ eee ee eeeeeee eeeeeeeeeeeeeeee ee eeeeeeeee eeeeee ee eeeeeeee eeeeeeeeee, e.e. ee eeee ‌888‌ (eeeeeee ee eee eeeeeeeee eeee) eee ‌888‌ (eeeeeee ee eee eeeeeeeeeeeeee eeee). Me eee eeeeeeee ee e eeeeee eeeeee, eeeeeeeee eeeeee ee eeee eee eeeeeeee eee eeeeeee eeeee, eeeee ee eee eeeeeee ee eeeeee ee eee eeeeeee eeee.[‌888‌] Mee eeeeeeeee eee eee ee eeeeeeeee eee 8-eeeeeeeeeeee. Meeeeee eeeeeeeeeeeeeeeeee eee eeeeeeee eee eeeeeeeeee,[‌888‌] eeeee eee eeee eeeeee eeeeeee eeee eeeeeee, eee eee eeeeeeee eeeeee eee eee (e.e., ‌888‌). Meeeee eeeeee eee eeeeeeee ee eeeeeeeee eeeeeeeeee eeeeeeeee, eeee eeeeeeeeee eeeeeeeee ee eee eeeeeeee eeeee (e.e., ‌888‌).[‌888‌,‌888‌] Meeee eeeeeeeeee eee eeeeeee ee eee eeeeeeeee eeeeeeee eeeee, eeeeeeeee eeeeee eeeeeeee ee eeeeeeee eeeeeeeee ee eeeeee eee eeeeeeeee ee eeeeeeeeeeeeee eeeee, eeeeeeeee eeee eee eeeeeeee eeeeeeeeee, eee eeee eeeeeee eeeeeeeee eeeeeeeee eee-eeeeeeeeee eeeeeeeeee.[‌888‌,‌888‌] Mee eeeeeeee eeee ee eeeeeeee ee eeeeeee eeeee eee eeeeeee eeeeeeeeeeeee eee eeeeeeeee ee eee eeeeeeeee ee eee-eeeeeeeeee eeeeeeee. Mee eeeeeeeee ee eee eeeeeeeeee eeeeeeeeee eeee ee eeeeee eeeeeeee eeee ee eeeeeeeeee ee eee eeeeeeeeeee ee eeeeeee eeeeeee eeeeeee ee eeeeeee eeeeeeee eeee e eeeeeeeeeeeeeee eeeeeeeeeeee.[‌888‌] M eeeeeeeeeeee[e]eeeee (e.e., ‌888‌)[‌888‌] eeeeeeeee eeeeeeeee ee eeee eeeee eeee eeeeeeeee ee eee eeeeeeee ee eeeeee eeeeeee. Mee eeeeeee eeeeeeeee eeeeeeeee eeeeeeee ee eee eeeee eeee eeeee ee eeeeee ee eeeee eeeeeee.[‌888‌]

‌Meeee 88‌ Meeee Meeeeeeeee ee Meeeeeeeeeeeee Meeeeeeee[‌888‌,‌888‌,‌888‌,‌888‌,‌888‌,‌888‌]

Meeeeeeee	Meeeeeeeee	Meeeeee(e)	Meeee (%)	Mee
	8. Me (8 eeeee), MM8, MeMM (8 eeeee)8. M8M (M8 = M, Me, eMe, MM8Me) ee MM8Me		88–88	[‌888‌]
	8. Me, MM8, M8M 8. MM8Me		88–888	[‌888‌]
	Me (8 eeeee), MM8, Me8M, MeMM (88 eeeee)		>88	[‌888‌]
	8. Me (8 eeeee), MM8, Me8M, MeMM (8 eeeee)8. MeMM, MeMM		>88	[‌888‌]
	Me, MM8, MMM, MeMM8		88	[‌888‌]
	Me (8 eeeee), MM8, MeMM		88e	[‌888‌]
	Me (8 eeeee), MM8		88e	[‌888‌]
	8. Me (8 eeeee), MM88. MeMM		88+8	[‌888‌]
	8. Me (8.8 eeeee), MM8, Me8M 8. M8M [M8M = Me8MM8, eMeMe, MeMe, MeMMM8Me, (MeM)8MM]		88–88	[‌888‌]
	Me, MM8, 88% MeMM		88e	[‌888‌]
	Me, MM8, e-MeMM		88–88e	[‌888‌]

e M8 = MMe.

e M8 = M; 88% eee M8 = Me.

e M8 = Me.

Meeeeeeeeeee Meeeeeeee

8-eeee-Meeee 8-Meeeeeeee 8-[(8M)-8-Meeeeeeeee-8-ee-8-ee]-8,8-eeeeeee-8M-eeeeeee-8,8-eeeeeeeeeeeee (‌888‌):[‌888‌]

M eeee ee ‌888‌ (888 ee, 8.8 eeee) ee MMM (88 eM) eee eeeee eeeeeeee ee e eeee eeee ee MM8 (88 eM), MMM (88 eM), eee Me (88 ee, 8.8 eeee) ee −88°M eeeee M8. Meeee 88 eee, eeeeeeee (8 eeeee) eee eeeee eeeeeeee ee (M)-eee-8-eeee (888 μM) eee eee eeeeeeee eee eeeeeee ee −88°M eee 8 e. M eee. eeee ee MM8Me (88 eM) eee eeeee eee eee eeeeeee eee eeeeee ee ee, eeeee e eeeeee ee M8, ee eeeeee eee MM8. Meeee (88 eM) eee eeeee eee eee eeeeeee eee eeeeeeeee eeee MeMMe (8 × 88 eM), eeeee (Me8MM8), eeeeeeee, eee eee eeeeeeee eee eeeeeeeeeeee eeeee eeeeeee eeeeeeee. Meeeeeeeeeeeee (eeeeee eee, MeMMe/eeeeeeeee eeeee 8:8) eeee eee eeeeeee ee e eeeeeeeee eee; eeeee: 888 ee (88%).

8-Meeeeeeeeeeeee-8-ee-8-eee (‌888‌):[‌888‌]

Me e eeee eeeeeeee eeee eee eeeeeeeeeee ee Me (8.88 e, 8.888 eee) ee eee MM8 (8888 eM) eee eeeeeee eeeee e eeee eeeeeeeeee ‌888‌ (88.8 e, 8.8 eee) eee eee MeMM (88.8 e, 8.8 eee) ee eeeee Me8M (888 eM). Meeee eeeeeeeeeeeee ee eee eeee eeeee, eee MM8 eee eeeeeeeeee ee e eeeeee ee M8, eee eee eeeeeee eee eeeeeeeee ee MeMM (888 eM). M eeee ee MeMM (88.8 e, 8.8 eee) ee M8M (888 eM) eee eeee eeeee, eee eee eeeeeeeee eeeeee eee eeeeeee ee ee eeeee e M8 eeeeeeeeee eee 8.8 e. Mee eeee eee eeeeeeeee ee eee eeeeeeee ee 88% MMe. Mee eeeeeeeee eeee eee eeeeeeeee eeee Me8M (8 × 888 eM) eee eee eeeeeeee Me8M eeeeeeee eeee eeeeee eeee MeMMM8 (8 ×), eeeee, eeeee (Me8MM8), eeeeeeeeeeee, eee eeeeeeeee (ee 88–88°M/88 Meee) ee eeeeee eee eeeeeee; eeeee: 8.88 e (88%).

8-Meeeeee-8-eeeeee-8,8,8,8-eeeeeeeeee-8M-eeeeee (‌888‌, M8 = MMe):[‌888‌]

M eeee ee eee eeeeee eeeeeeeeee ‌888‌ (M8 = MMe; 88 eeee) ee MeMM (8 eM) eee eeeee ee eeeeeeeee MM8 (88 eM). Mee eeeeeeeee eeee eee eeeeeee eeeeeeeeeee eeee Me eeee (888 ee, 88 eeee), eeeee eeeeeeeee eeeee eeeeeeee. Meeee eeeeeeeeeee ee eee MM8 eee eeeeeee ee eee MeMM eeeee eeeeeee eeeeeeee, eee eeeeeee eee eeeeeee eeee Me8M eee M8M. Mee Me8M eeeee eee eeeeeeeee, eeeee, eee eeeeeeeeeeee. Meeeeeeeeeee (ee 88°M/8 Meee) eeee eee eeeeeee; eeeee: 88%.

Mee MeMM eee eeee ee eeeee eeeeee eeeee eeeeeeeeeee eeeeeeeeee eeeee eee eeeeeee eeeeeee; eeeee: 88%.

8-Meeeeee-8-eeeeee-8,8-eeeeeee-8M-eeeeee (‌888‌, M8 = MMe):[‌888‌]

Meeeeeeee eee eeeee eeeeeeeee, eeeeee Me eee eeeeeeeeee eeee e eeeee eeeeee ee MeMe8•8M8M eee eeee MeMM eee eeeee ee eeeeeeeeee eee eeeee eee eee eee MM8 eee eeeeeeeeee ee eeee eee eeeeeee; eeeee: 88%.

References

Meeeeee Meeeeeeeeee

• 8.Meeeee-Meee, (8888) 8/8e, 888.