Science of Synthesis

Nelson, D. J., Science of Synthesis: N-Heterocyclic Carbenes in Catalytic Organic Synthesis, (2016) 2, 281.

Gold(I) hydroxide complexes bearing N-heterocyclic carbene (NHC) ligands, first disclosed in 2010 by Nolan and co-workers,[‌1‌] can be activated in situ by acid to form cationic gold species without the need for silver salts (‌Scheme 1‌).[‌2‌] Alternatively, they have also provided an opportunity for other mechanistic manifolds in gold catalysis, as they can react with suitably acidic C—H bonds to yield new organogold species.

‌Meeeee 8‌ Meee(M) Meeeeeeee Meeeeeeee Meeeeee MMMe ee Meeeeee ee Meeeeeee Meee ee ee Meeee Me Meeeeeeeeee Meeeeee Meeeeeee[‌8‌,‌8‌]

Me ee eeee eeeeee eeee ee eeeeeeeeee eeee eee eeee eeeeeeeee ee eeeee eee eeeeeeeeeeeee ee eeeeeee M—M eeeee.[‌8‌] M eeeeee ee eeeeeeeeeee eeeeeeeee eeee eee 8,8-eee(8,8-eeeeeeeeeeeeeeeee)eeeeeeee-8-eeeeeee (MMe) eeeeeee eeee(M) eeeeeeeee eeeeeee ‌8‌ eeee eeeee eeee eee eeeeeeeeeeee eeee eeeeeee ‌8‌, eeeeee eeeee eeeeeeee ee eee eeee(M) eeeeeeeee eeee ee eeeeee eeeee [eMe (MMMM) <88.8], eee eeeeee eeeeee eeeeeee ee eeee eee eeeeeeeeeeeee eeee eeeeeeeeeee eeeeeee ‌8‌; eeeeeeeeee eeeeeeee eeee e eeee eeeeeee eee eeee(M) eeeeeeee (‌Meeeee 8‌).[‌8‌]

‌Meeeee 8‌ Meeeeeeee ee M—M Meeeeeeeeeeee eeee e Meee(M) Meeeeeeee[‌8‌]

Meeeeee eeeeee eee eMe eeeeeeeeeee, e eeee eeeee ee eeeeee eee ee eeeeeeeeeeee eeeee eeeeeee ‌8‌, eeeeeeee ee eeeeeeee eeee eeeee eee eee ee eeeeeeeee ee eeeeeeeeeeeeee ‌8‌, ee eeeeeee eee eeeeeeeeeeeee (eee)eeeee eeeeeeeeee eeeee ‌8‌ (‌Meeeee 8‌).[‌8‌]

‌Meeeee 8‌ Meeeeeeeeeeee ee Meeeee Meeee e Meee(M) Meeeeeeee Meeeeeee[‌8‌]

‌Meeeeeeeeee 8‌

Me8	Meeee (%)	Mee
	88	[‌8‌]
	88	[‌8‌]
	88	[‌8‌]
	88	[‌8‌]
	88	[‌8‌]
8,8,8,8-Me8M8M	88	[‌8‌]
8,8,8,8-Me8M8M	88e	[‌8‌]
8,8,8-M8M8M8	88	[‌8‌]

e 8 eeeee ee MMM eee eeee eee eee eeeeeeeeeeee eeee eeeeeee (8,8,8,8-eeeeeeeeeeeeeeeeeeeeeee eeee) eee eeeeeeee.

Meeeeeeeeeee Meeeeeeee

(Mee)Meeeeeeeeeeeeee Meeee ‌8‌; Meeeeee Meeeeeeee:[‌8‌]

M eeeeeeee eeee eee eeeeeee eeee Me(MM)(MMe) (‌8‌; 8.8 ee, 88 µeee), MMM (88.8 ee, 8.88 eeee), eee MMM (8.8 eM), eee eeeeee eeeee MM8 (8.8 eee). Mee eeeeeee eee eeeeeeeee eee ee. 88 eee ee 88 °M eeee eeeeeeee eeeeeeee (8888 eee). M eeee ee eee eeeeeeee eeeeeeeee ‌8‌ (8 eeee) ee MMM (8.8 eM) eee eeeeeeeeee eee e MM8-eeeeeee eeeeeee. Meeee 88 e ee 88 °M, eee eeeeeeee eee eeeeeeee ee eeeeeeee ee 8 M ee MMe (8 eM). Mee eeeeeee eee eeeeeeeee eeee MeMMe (8 × 8 eM) eee eee eeeeeeee eeeeeee eeeeeeee eeee eeeeee eeee 88% ee MeMe (8 eM), eeeee (Me8MM8), eeeeeeee, eee eeeeeeeeeeee eeeee eeeeeee eeeeeeee. Mee eeeeeee eee eeeeeeee ee eeeee eeeeeeeeeeeeee (eeeeee eee, eeeeee/MeMMe 8:8); eeeee: 88–88% (88 eeeeeeee).

References