Science of Synthesis

Gleiter, R.; Werz, D. B., Science of Synthesis, (2008) 43, 644.

Ring-closing-metathesis reactions between two terminal double bonds or two methylated alkyne units belong to the most powerful procedures to construct rings of medium or large size. Although ring-closing alkyne metathesis (RCAM) has been known since the 1970s,[‌75‌,‌76‌] it has taken rather a long time[‌77‌–‌81‌] to develop this method into a useful tool to synthesize large ring systems. This progress is due to improvements in the efficiency of the early available catalysts and the development of new ones.

Me eee eeeeee eeeee eee eeeee eeeeeeee eeeeeee ee eee eee MMMM (‌Meeee 8‌): (8) Mee ee-eeeeee Meeeeeee eeeeee eeeeeeeeee ee eeeeeeeeeeeeeeeeeeeeee(8) eee eeeeeee eeeeeee (eeeee 8, eeeeeeeee eeeeee M);[‌88‌,‌88‌,‌88‌–‌88‌] (8) eeee-eeeeeeeee-eeeee eeeeeeeeee– eee eeeeeeee–eeeeeeeeee eeeeeeeee (eeeee 8, eeeeeeeee eeeeee M);[‌88‌–‌88‌] eee (8) e eeeeeeee eeeeee eeee eeeeeeeeee eeeeee Me[M(e-Me)Me8]8 ee eeeeeeee eeeeee eee eeeeeeeeeeeeeee (eeeee 8, eeeeeeeee eeeeee M).[‌88‌]

Mee eeeee eeeeeeeee eeeeee M eee eeeeeeee ee Meeeeeee eee ee-eeeeeee.[‌88‌,‌88‌] Me eeeeeeee ee eeeeeeeeeeeeeeeeeeeeee(8) eeeee ee eeeeeeeee ee eeee ee eeeeeee. Mee eeeeeee eeeeee ee eee eeeeee eeeeeee ee eeeeeee eee ee ee eeeeeee eeee e eeeeeeeeee eeeeeeeeee eeeeeee ee eeeeee ee ee eeeeee eeeeeeeeeeee. Mee eeeeeeeee ee eeee eeeeeeee ee eee ee eee eeeeee eeeeeeeeeee eeee eee-eee-eeeee eeeeeeee.[‌88‌–‌88‌,‌88‌,‌88‌]

‌Meeee 8‌ Meeeeeeeeee Meeeeee eee Meeeeeeeee eee Meee-Meeeeee Meeeee Meeeeeeeee[‌88‌,‌88‌,‌88‌–‌88‌]

Meeee	Meeeeeeee Meeeee	Meeeeeeeeee Meeeee	Meeeeee	Meee (°M)	Mee
8	M	Me(MM)8 (8.88 eeeee), 8-eeeeeeeeeeee ee eeeeeeeeeeeee (8.8 eeeee)	eeeeeee ee eeeeeeeeeeeee	888–888	[‌88‌,‌88‌,‌88‌–‌88‌]
8	M		eeeeeee ee eeeeeeeeeeeee	88	[‌88‌–‌88‌]
8	M		eeeeeee ee MMM	88	[‌88‌]

Mee eee eeeeeeeee eeeeeee M eee M eeee ee ee eeeeeeee eeeeee eee. Mee eeeeeeeee ee eeeee eeeee eeeeeeeee eeeeeee eee eeeee eeeeeeeeeeee (88°M) eee eee eeeeeeee eee e eeeeeee eeeeeeeee eeeeee eeeeeeeeee eeeeee. Meee eeeeee eeee ee eeeeeeeeeeee ee eee eeeeeeeeee ee MMMM eeeeeeeee eeeeeee eeeeeeeeeeee ‌88‌ eeeee eeeeeeeee eeeeeee M eee M (‌Meeee 8‌).[‌88‌] Meee eeeeeeeeee eeeeeee eeee eeeeeeeeeeeeee eeeeee (eeeeeee 8 eee 8), eeeee eeeeee (eeeee 8), eee eeeeeeeee eeeeee (eeeee 8) eee eeeeeeeeeeee eeee eeeeee M eee eeee eeeeeeeeeeee eeeeeee eeee eeeeee M.

Mee eeeeeeeee eeeeee M ee eeeeeeeeee ee eeee ee M. Me eeeeeeeee eeee eeeeeeeeee eeeeee eee eeeeeeee eeeee eeee eeeeeeeeee (88°M). Meee eeeeeeeeeeeeee eeeeeeee eee eeeee ee ‌Meeee 8‌.[‌88‌] Me ee eeeeeeeeee eeee eeee eeeeee eeeeeeeeeeeeeeeee eee eeeeee eeeee-eeeeeeeeee eeeeeeeee eeee eeeeeeeee eeeeee.

‌Meeee 8‌ Meee-Meeeeee Meeeee Meeeeeeeee Meeeeeeee Meeeeeeee ee Meeeeeeee Meeeeee M eee M[‌88‌]

Meeee	Meeeeeeee	Meeeeee	Meeee (%)		Mee
			Meeeeeeee Meeeee M	Meeeeeeee Meeeee Me
8			88	88	[‌88‌]
8			8	88	[‌88‌]
8			88	88	[‌88‌]
8			–e	88	[‌88‌]
8			8	88	[‌88‌]
8			8	88	[‌88‌]
8			88	88	[‌88‌]

e Meeee eee eeeeeeee-eeeee eeeeee.

e Meeeeeeeee.

‌Meeee 8‌ Meee-Meeeeee Meeeee Meeeeeeeee Meeeeeeee ee Meeeeeeee Meeeee M[‌88‌]

Meeee	Meeeeeeee	Meeeeee	Meeee (%)	Mee
8			88	[‌88‌]
8			88	[‌88‌]
8			88	[‌88‌]
8			88	[‌88‌]
8			88	[‌88‌]
8			88	[‌88‌]

M eeee-eeeeeee eeeeeeeeee eeeeeeee ee α,ω-eeeeee ‌88‌ eeeee eee eeeeeeeeee ee eee eeeeeee eeeee eeeeeeeeeeeeeeeeeeeeee(8) (eeeeeeeee eeeeee M) ee eeeee ee ‌Meeeee 88‌. Mee e eeeeee eeee 88 eeeeeeeee eeeeeeeee eeeeee (‌88‌, e = 88) eeeeeee eee eeeeee eeeee eeeeee eeeeee ‌88‌ ee eeeeeeee ee 88% eeeee. Mee eee eee eeeee eeeeeee eeee e eeeeeee eeeeee ee eeeeeeeee eeeeeeeee eeeeee eee eeeeeeeeeeeee eeeeee eeeeee ‌88‌ eee eeeeeeee.[‌88‌]

‌Meeeee 88‌ Meeeeeeeeee ee e Meeeeeeeeee eee Meeeeeeeeeeeeee ee Meee-Meeeeee Meeeee Meeeeeeeee[‌88‌]

Meeeeeeeeeee Meeeeeeee

Meeeeeeeeeee, e.e. ‌88‌; Meeeeee Meeeeeeee eee Meee-Meeeeee Meeeee Meeeeeeeee Meeee Meeeeeeeeee M:[‌88‌]

MMMMMMM: Meeeeeeeeeeeeeeeeeeeee(8) ee eeeeee eeeee.

M eeee ee eee eeeee eeeeeeeee (8.8 eeee), 8-eeeeeeeeeeee (8.8 eeee), eee Me(MM)8 (8.888 eeee) ee eeeeeeeeeeeee (888 eM) eee eeeeeeee eeeee MMM eeeeee eeeeeeee eeeeeeeeee ee eee eeeeeeee eeeeeeee (eeeeeee 8–88 e). Meeeee eeee eeeeee, e eeeeee eeeeee ee eeeee eee eeeeeee eeeeeee eee eeeeeee. Meeeeeeeeeeee eeeee eeeeeee eeeeeeee eee eeeeeeeeeeee ee eee eeeee eeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeee/MeMMe ee eeeeeeeee eeeeeeeeeee) eeeeeeee eee eeeeeeeeeeee ee eee eeeeee eeeeeeeee ee ‌Meeee 8‌.

Meeeeeeeeeee, e.e. ‌88‌; Meeeeee Meeeeeeee eee Meee-Meeeeee Meeeee Meeeeeeeee Meeee Meeeeeeeeee M:[‌88‌]

M eeee ee eee eeeee eeeeeeeee (8.8 eeee) eee (e-MeM)8M≡Me-Me (8.888 eeee) ee eeeeeeeeeeeee ee eeeeeee (88 eM) eee eeeeee ee 88°M eee 8.8–8 e eeeee eeeee. Meeeeeeeeeeee eeeee eeeeeee eeeeeeee eee eeeeeeeeeeee ee eee eeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeee/MeMMe ee eeeeeeeee eeeeeeeeeee) eeeeeeee eee eeeeeeeeeeeee eeeeeeeeeeee ee eeeeeeeeeeee eeee eeee ee eee eeeeee eeeeeeeee ee ‌Meeee 8‌.

8,88-Meeeeeeee-8,8,88,88-eeeeeeeeee[8,8]eeeeeeeeeeeeeeeeee[8,8-e]eeeeeeee--8,88-eeeee (‌Meeee 8‌, Meeee 8); Meeeeee Meeeeeeee:[‌88‌]

MM8Me8 (888 μM) eee eee eeeeeeeeeeeee eeeee (888 ee, 8.88 eeee) eeee eeeeeeeeeeee eeeee ee e eeeeeee eeee ee Me[M(e-Me)(M8M8-8,8-Me8)]8 (888 ee, 8.88 eeee) ee eeeeeee (88 eM) eee eee eeeeeeeee eeeeeee eee eeeeeee ee 88°M eee 88 e. Mee eeeeeee eee eeeeeee eeeee eeeeeee eeeeeeee eee eee eeeeeee eee eeeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeee/MeMMe 8:8) eeeeeeeee eee eeeeeee ee e eeeeeeeee eeeee; eeeee: 888 ee (88%); ee 88–88°M.

Meeeeeeeeeeeeee, e.e. ‌88‌; Meeeeee Meeeeeeee eee Meee-Meeeeee Meeeee Meeeeeeeee:[‌88‌]

MMMMMMM: Meeeeeeeeeeeeeeeeeeeee(8) ee eeeeee eeeee.

M eeeee-eeeeee 888-eM eeeee eeeeeeee eeee e eeeeeeee eeeeee eee e eeeeeeeee eee eeeeeee eeee eeeee eee eeeeeee eeee e eeee ee Me(MM)8 (88 ee, 88 eee%) eee 8-(eeeeeeeeeeeeeee)eeeeee (8.8 e, 8.8 eeee) ee eeeeeee (88 eM). M eeee ee eee eeeeeeeeee eeeeeeee ‌88‌ (8.8 eeee) ee eeeeeee (88 eM) eee eeeee eeeeeeee eeee e eeeeee ee 8.8 e ee 888°M. Meee eee eeeeeeee eee eeeeeeee, eee eeeeeee eee eeeeeee ee ee eeeee ee eeeeeeee eeeeeeee eeeee ee eeeeeeee. Meeeeeeeeeeee eeeee eeeeeee eeeeeeee eeeeeeee ee eeeeee eeeeeeeeeeeeee ee eee eeeeeee (eeeeeeeee eeeee/Me8M 888:8) eeeeeeee eee eeeeeeee ee eeeeeeeee eeeeeee ee eeeeee.

References