Science of Synthesis

Evano, G., Science of Synthesis, (2007) 20, 1275.

Propynoic acid esters undergo deprotonation under the action of a strong base (typically butyllithium or lithium diisopropylamide) to form the lithium acetylide, which can react with a wide range of electrophiles such as aldehydes, ketones, epoxides, nitrones, or alkyl halides to form the corresponding substituted alk-2-ynoic acid esters. This synthetic route to alk-2-ynoic acid esters is supplementary to those described in the above paragraphs, as it allows for the introduction of a different substitution pattern while giving a straightforward access to enantiopure, substituted alk-2-ynoic acid esters, because the electrophilic partners are usually available in both enantiomeric forms.

Meeeee ee eeeeeeeee eeeee ee eeeee eeeeeeeeeee eeee eee eeeeee ee eeeeeeee eeeeeeee ee eeeeeeeee. Meeeeeee eeeeeeee eeeee ee e eeeeeee eeeeee eeee eeeeee ee eeeeeeeee eeee eee ee eee eeeeee ee eeeeeee eeee eee eeeeeee eeeeeeeeee eeeee. Meeeeee, eee eeeeeeeeeeee ee eeeeeee eeeeeeeeee, eeeeeee eeee eeeeeeeeeee, eeee eeeeeeeee ee e eeeeeeee eeee eee eee eeeeeeeee ee eee-8-eeeee eeee eeeeee, e.e. ‌88‌, eeeeeeeeee e eeeeeeeee eeeeeee ee eee α-eeeeeeee (‌Meeeee 88‌). Meeee eeeeeeeeee eeee eeee eeeeeeeeeeee eeeeeeee ee eee eeeeeee ee Meeeeeeeeeee[‌888‌] eee Meeeeee.[‌888‌] Mee eeeeee eee eeeeeee eeeeeeeee eeee eeeeeeeee eeeeeee ee eeeeee eeeee eeee ee eeeeeee eeeeeeeeeeeeeeee ee eeeeeee eeeeeeeeeeeeeeeeeeeeee, eeeee eeeeee eeeee eeeeeeee eeee eeeeeeeeeeee ee e eeee, eeeee eee eeeeee ee eeeeeeeee ee eeeeeeeeeee eeeeeeee ee eee eeeee. Meeeeeeeeee eee eeeeeeeeeeeee eeeeeee, eee eeeeeee ee eeeeeeeee, eeee eeeeee eeee eeee ee ‌88‌,[‌888‌] ‌88‌,[‌888‌] ee ‌88‌[‌888‌] ee eeeeeeeee eeee eeee ee ‌88‌[‌888‌] ee ‌88‌,[‌888‌] eeee eeee eeee ee eeee eeeeeeeeeeee. Me eeeeee ee eeeeeee eeeeeeeee eeee eee eeeeeeeeee eeeeeeee eeee eeee eeeeeeee eeee ee α,β-eeeeeeeeeee eeeeeeee eeee ee ‌88‌[‌888‌] ee eeee, eee eeee eeeee ee eeeeeeeeeeeeeeeee eee ee eeeeeeee eeee ee α-eeeeee eeeeeeee, e.e. ‌88‌, ee eeeeeee.

‌Meeeee 88‌ Meeeeeeee ee Meeeeeee ee Meeeeee Meeeeeeeeee ee Meeeeeeee[‌888‌–‌888‌]

Meeeeeee eeeee eeeeeeee eee eeee eeee ee eeeeee eeeee ee eee eeee ee eeeeeeeeee eeeeeeee ee eeeeeeeee, eee eeeee eeeeeeeeeeeeeeee eeeeeeee ee eeeeeeeeee eeee eeeeeeeee eee eeee eeeeeeee ee 8888.[‌888‌] Me eeeeeeee eeeeee eeeeeeeeee eeee eeeeeeeeeee ee eee eeeeeeee ee (M)-MMMMM eee eeeeeeeeeeeeeeeeeeee eeeeeeee ee eeee eeeeeeeeeee eeeeee eee eeeeeeee ee eeeeeeee(MM) eeeeeeeeeeee eee eeeeeeee eeeeeeeee, α-eeeeeeeeee-8-eeeee eeee eeeeee ‌88‌ eeeee ee eeeeeeee ee eeeeeeeee eeeeee eee eeeeeeeeeeeeeeeeeeee (‌Meeeee 88‌).

‌Meeeee 88‌ Meeeeeeeeeeeeeee Meeeeeeee ee α-Meeeeeeeee-8-eeeee Meee Meeeee ee Meeeeeeeee Meeeeeee ee Meee-8-eeeeeee ee Meeeeeeee[‌888‌]

8-Meeeeeeeee-8-eeeeeee eee eeee ee eeeeeeee ee eeeeeeee eeeeeee eeee eeeeeee eeeeee­eeeee eeeeeeeee ee eee eeeeeeeee eeeeeeee ee Meeeeee.[‌888‌,‌888‌] Mee eeeeee ee eee eee-8-eeeee eeee eeeeee ‌88‌ eeeeeeee eeee eeee eeeeeeeee eee eeeeeee eeee eeee eee eee eeeeee eee eeee eeeeee eeee; eeee eeeeeeeeeeeeee eeeeeeee eee eeeeeeeee ee ‌Meeee 88‌.

‌Meeee 88‌ Meeeeeeee ee Meeeeeee ee Meeeeee Meeeeeeeeee ee Meeeeee[‌888‌–‌888‌]

M8	Meeeeeeeee, Meee 8	Meeeee	Meeeeeeeee, Meee 8	Meeee (%)	Mee
Me	MeMe, MMM, –88°M		–88°M, 8 e	88	[‌888‌]
Me	MMM, MMM, –88°M, 88 eee		–88°M ee ee	88	[‌888‌]
Me	MMM, MMM, –88°M, 8 eee		–88°M, 8 e	88	[‌888‌]
Me	MMM, MMM, –88°M, 8 e		–88°M, 88 e	88	[‌888‌]
Me	MeMe, MMM, –88°M, 88 eee		–88°M, 8.8 e	88	[‌888‌]

Meeeeeeeeee eeeeeeee eeeeeeeeeee eee eeee ee eeee eee eee eeeeeeeeeeee ee eeeeeee eeee eeeeeeeeeee ‌88‌. Meee eeeeee eee eee ee e eeeee eeeee ee eeeeeeeeee ee eeee eeeeeeeeeeee eeeeeeee. Meeee eee ee-eeeeeee eeee eeeeeeeee eee eeeeeeeee eeeeeeeeeeee ee eeeeeee eeeeeee eeee e eeeeeee ee eeeeeee, eeeeeeeee eeeeeeeeeee, eeeee eeeeeeeeeeee eeeeeeeee eeeeeeeeeeeeeeeeeeeeeee eeeeeeeee (Meeeee M) ee e eeee (‌Meeeee 88‌).[‌888‌] Meee eeeeeeee e eeeeee eeeeeeeeeee eeeeeeee eee eee eeeeeeeee ee eee-8-eeeee eeee eeeeee ee e eeeeeeeee eeeee, eee eee eeeeeeee eee eeeeeee eeeeeeee ee eeeeeeeeee ee eeee eeeeee.

‌Meeeee 88‌ Meeeeeeee ee Meeeeeee ee Meeeeeee Meeeeeeeeee ee Meeeeee[‌888‌]

Meeee eeeeeeeeee eeeee eeeeeeeeeeeeeeeee eeeeeee ee eeee eeee eeee eeee ee Meeeeee[‌888‌] (88 eee% eeeeee eeeeeeeee ee eeeeeeee eeeeeeeee) eee Meeeee[‌888‌] (88–88 eee% eeeeeeeee eeee-eeeeeeee ee eeeeeeee eeeeeeeee) ee eee eeeeeeeee eeeeeeee ee eeeeeeee eeeeeeeeee ee eeeeeeeee eee eeeeeee. Meeeeeee eee ee-eeeeeee[‌888‌] eeee eeeeeeeee e eeee eeeeee eee eee ee eeee eeeeeeeee eeeeeeeeee ee eeeeeeee eeee eeeeeeeeee, eeeee eee ee eeeeeeee, eeeeee, eee eeeeeeeee ee eeee eeeeeeeeeee eeeeeeeeeeeeee, eeeeee, eee eeeeeeee, eeeeeeeeeeee. Meeeeeeeeeeee, eee ee eeeee eeeeeee eeee eeee eeee eee eeeeeee ee eeeeeeee eeeeeeeeee eeeeeeeeee eeee ee eeeeeeeeeee eeeeeee ee eee eeeee eeeeeeee ee eeeee eeeeeeeee ee eeee eeee-eeeeeeee eeeeeeeee eeeee eeeee eeeeeeeeee.[‌888‌]

Meeeeeee ‌88‌ eeee eeeee eeee eee eeeeeee eeeeee ee eeeeeeeeeee ee eeee eee M-eeeeeeeeeeee-eeeeeeeeeee eee-8-eeeee eeee eeeeee ‌88‌ (‌Meeeee 88‌) ee eeeeeeeee eeeeee.[‌888‌] Meee eeeeee ee eeeeeeeeeeeeeeeeeee eeee eeee eeeeeeee eeee eeeee ee α-eeeeee eeeeeee ee eee eeeeeeee, eeeeeeeeee eeee e Meeee eeee (eeeee eeeeeeeeeee–eeeeeee eeeee eeeeeee ee eeeeeeeeeeeeeee eeeeeeee) ee eeee ee ee eeeeeeee.[‌888‌,‌888‌]

‌Meeeee 88‌ Meeeeeee ee Meeeeee Meeeeeeeeee ee Meeeeeee[‌888‌]

Meeeeee eeeee ee eeeeee eeeeeeeeeeeee eeee eee eeeee eeee eeeeeeeee eeeeeeeeeee ee eeeeeeee. Meeee eeeeeeeeeeeeee, eeeee eeeeeeeeeee eeeeeeee eeeeeee eee e eeeeeeeee eee eee eee eeeeeeeee ee eee-8-eeeee eeee eeeeee eeeeeee e eeeeeeeeeeee ee eee β-eeeeeeee (‌Meeeee 88‌).[‌888‌]

‌Meeeee 88‌ Meeeeeee ee Meeeeee Meeeeeeeeee ee Meeeeeee[‌888‌]

Meeeeee, eeeeee eeeeeeeeeee eee ee eeeeeeeeeeeeee ee eeeeeee eeeee eeeeeee, eeeeeeeee eeeee eeeeeeeeeeeeee eeee eeeeee eeeeeeeeeee eeeeeeee ee eeeee eeeeeeee eeee eeee eeeeeeeee[‌888‌,‌888‌] ee eee eeeeeeee ee eeeeee eeee eee eee eeeeeeeee eeeeeeee eeee eeeeeee eeeeee­eeeee eee eeeeeeeeeeeeeee.[‌888‌] Meeeeeee ee eeeeeee eeeeeeeeeee ee eeeeeeeeeeeeee eeeee ee eeee e eeeeee eeeeeeeee eeee.[‌888‌]

Meeeeeeeeeee Meeeeeeee

Meeee 8-Meeeeeeeee-8-eeeeee (‌88‌); Meeeeee Meeeeeeee:[‌888‌]

Me e eeee ee eeeee eeeeeeeeee (8.8 eM, 88.8 eeee) ee e MMM/Me8M/eeeeeee eeeeeee (8:8:8, 88 eM) eee eeeee e 8.8 M eeee ee MeMe ee eeeeee (88.8 eM, 88.8 eeee) ee −888°M eeeeeeee eeee 88 eee. Mee eeee eee eeeeeee eee 88 eee eee eeeeeee (‌88‌; 8 eM, 88.8 eeee) eee eeee eeeee. Mee eeeeeeeee eeeeeee eee eeeeeee eee 88 eee ee −888°M, eeeeeeee eeee MMMMe (8.88 eM, 88 eeee), eee eeeeee ee ee. Mee eeee eee eeeeeee eeee Me8M (88 eM) eee eeeeee eeee M8M (888 eM). Mee eeeeeee eeeee eee eeeee (MeMM8), eeeeeeee, eee eeeeeeeeeeee. Mee eeeeeee eee eeeeeeeee eeeeeee e eeeee-eeee eeeeeeeeeeee eeee (888°M/8.88 Meee) ee eeee eee eeeee; eeeee: 8.88 e (88%).

Meeee 8-Meeeeee-8,8-eeeeeeee-8-(eeeeeeeeeeeeeee-8-eeeee)eeeeeeeeee (‌88‌, M8 = Me; M8 = Me; M8 = MM8MMe8MMMM); Meeeeee Meeeeeeee:[‌888‌]

Me e eeee ee eeeee eeeeeeeeee (8.8 e, 88 eeee) ee MMM (88 eM) eee eeeee e 8.8 M eeee ee MMM ee MMM (88 eM, 88 eeee) ee −88°M. Mee eeee eee eeeeeee eee 88 eee, eee e eeee ee 8-eeeeee-8-(eeeeeeeeeeeeeee-8-eeeee)eeeeee-8-eee (8.8 e, 88.8 eeee) ee MMM (88 eM) eee eeeee. Mee eeeeeeeee eeeeeee eee eeeeeee eee 88 eee ee −88°M eee eeee eeeeeee ee eeee ee ee. M eee. MM8Me eeee eee eeee eeeee, eee eee eeeeeee eeeee eee eeeeeeeee (Me8M). Mee eeeeeeee eeeeeee eeeeee eeee eeeeee eeee eeeee, eeeee (MeMM8), eeeeeeee, eee eeeeeeeeeeee. Mee eeeeeee eee eeeeeeee ee eeeeeeeeeeee ee e Meeeeeeee eeeeeeeee (888–888°M/8.8 Meee) ee eeee eee eeeee ee e eeeeeeeee eee; eeeee: 8.88 e (88%).

References

Meeeeee Meeeeeeeeee

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