Science of Synthesis

Krueger, A., Science of Synthesis, (2008) 43, 478.

Another valuable source for the synthesis of alkynes by rearrangement are alkylidenecarbenes.[‌36‌–‌38‌] They rearrange by the migration of hydrogen atoms or other groups, usually aryl moieties. Alkylidenecarbenes can be produced in different ways, including the decomposition of (diazomethyl)phosphonates,[‌39‌] N-aziridinylimines,[‌40‌] or 3-nitrosooxazolidin-2-ones (‌Scheme 14‌).[‌41‌] They can be also obtained by the base-induced reaction of alkenyl trifluoromethanesulfonates[‌42‌] with diazoalkanes, and in general by an α-elimination of HX from R12C=C(H)X.[‌36‌–‌38‌,‌41‌] The trifluoromethanesulfonate anion is an excellent leaving group and a weak nucleophile, which promotes the formation of the carbene.[‌42‌,‌43‌] In combination with the strongly ionic K+ counterion, there is only a very low tendency for association with the carbene. The presence of a carbenoid structure can hence be excluded (see also Section ‌43.8.2.1.5‌ for examples of carbenoid intermediates in the Fritsch–Buttenberg–Wiechell rearrangement).

‌Meeeee 88‌ Meeeeeeeee ee Meeeeeeeeeeeeeeeee[‌88‌–‌88‌,‌88‌]

Meeeee eeeeeeeeeee eeeeeeee eeee ee eeeeeeeeeeeeeeeeee eeeeeee e eeeeee eeeeeeeeeeee eeeeeeeee eee eee eee eeeee ee eeeeeeeee eeee eeeeeee.[‌88‌] Me eeee eeeeeee, eeee eeeeeeeeeeeeee ee eeeeeeeeeeee eeeeeeeeeeeeeeeeee eeee ee eeeeeeeee.

M eeeee eeeeeeee eeee eeeeeeee eee eeeeeeeeeeeeeeeeee ee eeee eeeeeee ee eee Meeeee eeeeeeeeeeeee (‌Meeeee 88‌).[‌88‌] Meee eeeeeeee eeeeee eee eee eeeeeeeeeeeeee ee eeeeeee ‌88‌ eee eeee eeeeeeeee[‌88‌,‌88‌] eeee eee eeeeeeeeee eeeeeee ‌88‌ ee M-eeeeeeeee eee eeeeeeeee ee eee eeeeeee, eeee eeeee ee eeee eeeee. Mee eeeeee eeeeeeeee eee eeeeeeeee ee eee eeeeeeeeeeeeeeeee ee eeeeeeee ee eee eee ee (eeeeeeeeeeeeee)eeeeeeeeeeee[‌88‌–‌88‌,‌88‌] ee (eeeeeeeeeee)eeeeeeeeeee.[‌88‌] Meeee eeeee eeeeeeeeee, eee eee ee eeeeeee eeee eeeeee eeeeeeeeee eeeeeeeee ee eee eeeeeeee. Meeeeee, Meeeeee eee ee-eeeeeee eeee eeeee eeee eeeee eeeeeeeee eeee-eeeeeeee eee eeeeee eeeeeeee eeeee ee eeeee eeeeeeeeeeee ee eeeeeeeee eee eeeeee eeeeeeeee eeee eeee eeeee eeeeeeeee eeeeeeeeee.[‌88‌]

‌Meeeee 88‌ Meeeee Meeeeeeeeeeee ee Meeeeee[‌88‌,‌88‌,‌88‌–‌88‌]

‌Meeeeeeeeee 88‌

M8	M8	Meeeeeeeee	Meeee (%)	Mee
Me	Me	MMMMMM8, MeMe, Me8M, 8°M	88	[‌88‌]
Me	Me	MMMMMM8, MMM, MMM, −88°M, 8 e, eeee eeeeee, 8 e	88	[‌88‌]
Me	Me	MMMMMM8, MMM, MMM, −88°M, 8 e, eeee eeeeee, 8 e	88	[‌88‌]
Me	eMe	MMMMMM8, MMM, MMM, −88°M, 8 e, eeee eeeeee, 8 e	88	[‌88‌]
Me	Me	MMMMMM8, MMM, MMM, −88°M, 8 e, eeee eeeeee, 8 e	88	[‌88‌]
8-MeMM8M8	Me	MMMMMM8, MMM, MMM, −88°M, 8 e, eeee eeeeee, 8 e	88	[‌88‌]
8-eeeeeeee	Me	MMMMMM8, MMM, MMM, −88°M, 8 e, eeee eeeeee, 8 e	88	[‌88‌]
8-eeeeeee	Me	MMMMMM8, MMM, MMM, −88°M, 8 e, eeee eeeeee, 8 e	88	[‌88‌]
8-eeeeeee	Me	MMMMMM8, MMM, MMM, −88°M, 8 e, eeee eeeeee, 8 e	88	[‌88‌]
8-M8MM8M8	M	8. (MeM)8M(M)MMM8; 8. Me8M; 8. e-MeMM	88	[‌88‌]
8-M8MM8M8	M	(MeM)8M(M)MMM8, e-MeMM, MMM, −88°M, 88 e, eeee ee, 8 e	88	[‌88‌]
8-MeMM8M8	M	MMMMMM8, MMM, MMM, −88°M, 8 e, eeee eeeeee, 8 e	88	[‌88‌]
(MM8)8Me	M	MMMMMM8, MMM, MMM, −88°M, 8 e, eeee eeeeee, 8 e	88	[‌88‌]
(M)-MM=MMMe	M	MMMMMM8, MMM, MMM, −88°M, 8 e, eeee eeeeee, 8 e	88	[‌88‌]
	M	MMMMMM8, MMM, MMM, −88°M, 8 e, eeee eeeeee, 8 e	88	[‌88‌]
	M	MMMMMM8, MMM, MMM, −88°M, 8 e, eeee 8°M, 8 e	88e	[‌88‌]
Me	M	(MeM)8M(M)MMM8, e-MeMM, MMM, −88°M, 88 e, eeee ee, 8 e	88	[‌88‌]
Me	Me	(MeM)8M(M)MMM8, e-MeMM, MMM, −88°M, 88 e, eeee ee, 8 e	88	[‌88‌]
M	MM(Me)MMMM	MMMMMM8, MeMe, MMM/eeeeeee	88	[‌88‌]
eMe	MM(Me)MMMM	MMMMMM8, MeMe, MMM/eeeeeee	88	[‌88‌]

e >88% ee (ee 8M MMM).

Me eeee eeee eeeeeeeee eeeeeeee ee eeee eeee ee eee Meeeeeee–Meeee eeeeeeee, eeeee eee eeee eeee ee eeeeeeeeee e eeeeeee ee eeeeeee (e.e., ‌88‌) eeee eee eeeeeeeeee eeeeeeeee ee eeeeeeee eee eeeeee eeee eeeeeeee (8-eeeee-8-eeeeeeeee)eeeeeeeeeee (‌Meeeee 88‌).[‌88‌–‌88‌] M eeeeeee ee eeeeeeeeee eeeeee ee eeeeeeeee, eeeeeeeee eeeeee, eeeeee eeeeee, eee eeeeeee, ee eeee ee eeeeeeeeeeeee eeeeee eeeee. α,β-Meeeeeeeeee eeeeeeeee eee eeeeeeeeeee eeee eee eeeeeeeeeeeeeee eeeeee eeeeee. Meeeeeee-eeee eeeeeeee eeeeeeeee ee eee eeeee eeeeeeeeee.[‌88‌]

‌Meeeee 88‌ Meeeeeee–Meeee Meeeeeee eee Meeeeeeeee Meeeeeeee eeee Meeeeee[‌88‌,‌88‌]

‌Meeeeeeeeee 88‌

Meeeeeeee	Meeeeeeeee	Meeeeee	Meeee (%)	Mee
Me(MM8)88MMM	eeeeeeeeeee (8.8 eeeee), M8MM8, MeMM, ee, 8–88 e	Me(MM8)88M≡MM	88	[‌88‌]
	eeeeeeeeeee (8.8 eeeee), M8MM8, MeMM, ee, 8–88 e		88	[‌88‌]
	eeeeeeeeeee (8.8 eeeee), M8MM8, MeMM, ee, 8–88 e		88	[‌88‌]
	eeeeeeeeeee (8.8 eeeee), M8MM8, MeMM, ee, 8–88 e		88	[‌88‌]
	eeeeeeeeeee (8.8 eeeee), M8MM8, MeMM, ee, 8–88 e		88e	[‌88‌]
	eeeeeeeeeee (8.8 eeeee), M8MM8, MeMM, ee, 8–88 e		88	[‌88‌]
	eeeeeeeeeee (8.8 eeeee), Me8MM8, MeMM, ee, 88 e		88	[‌88‌]

e Meeee eeeeeeeeee ee 8M MMM eeeeeeeeeeee.

8-Meee-8-eeeeeeeeeeeee ‌88‌ eee ee eeeeeeee ee eee eeeeeeee ee eeeeeeeeeeeee eeeeeeeee ‌88‌ eeee eeeee eeeeeeeeeeeeeeeeeeeeeeeeee ee eee eeeeeeee ee M,M-eeeeeeeeeeeeeeeeeeeee (‌Meeeee 88‌).[‌88‌] Meeee ee eee eeeeeeeee ee eee eeeee eeeee ee eeee e eeeeeeeee eeeee eeeeeeee ‌88‌ eeeee ee eee eeeeeeeeeeeee ee eee eeeeeee, eee eeeeeee ee eeee eeeeeeeee ee e eeeeeeeeeeee.

‌Meeeee 88‌ 8-Meee-8-eeeeeeeeeeeee eeee Meeeeeeeeeeee Meeeeeeee[‌88‌]

‌Meeeeeeeeee 88‌

8-Meeeeeeeeeeeeeeee-8-eeee ‌88‌ eeee eeeee ee e eeeeeeeee eeeeee ee eeeeeeeeeeeeeeeeee. Mee eeeeeeee eeeeeeeee eee ee eeeeeeee ee eeeeeeeeeee ee eeeeeeeeee-8-eeee. Mee eeeeee eee eeeeeeeee eeeeee eeee eee eeeeeeeeeeeee ee β-eeeeeee eeee eeeeee ee ee eee eeeeeeeeeee ee β-eeeee eeeeeeee eeee eeeeeeee, eeee, ee eeeeeee eeeeeeeee.[‌88‌] Meeee eee eeeeeeeee ee e eeee, eee 8-eeeeeeeeeeeeeeeee-8-eeee eeeeeeeee ee eeeee eee eeeeeeeeeeeeeeeeee. Mee eeeeee eeee eeeeeeeee ee eeee eee eeeeeeeeee eeeeeee (‌Meeeee 88‌).

‌Meeeee 88‌ Meeeeeeeeeeee ee 8-Meeeeeeeeeeeeeeee-8-eeee Me Meee Meeeeee[‌88‌]

‌Meeeeeeeeee 88‌

Meeeeeee eeeeeee eee ee eeeeee eeee α,β-eeeee-M-eeeeeeeeeeeeeeee. Me eeee eeee, eee eeeee eeee eeeeeeee ee e [8,8]-eeeeeeee eeeee (‌Meeeee 88‌).[‌88‌,‌88‌] Mee eeeee ee eee eeeeeeeeeeeee–eeeeeeeeeeeee eeeeeeee ee eeeeeee eeee (88–88%).

‌Meeeee 88‌ Meeeeeeeeeeee ee α,β-Meeee-M-eeeeeeeeeeeeeeee[‌88‌,‌88‌]

‌Meeeeeeeeee 88‌

e Meeeeeee eee eeeeeeee.

Mee eeeeeeeeeeeeeeeeee ‌88‌, eeeeeeeee eeee eeeeeee eeeeeeeeeeeeeeeeeeeeeeeeee, eeee eeeeeee eeeeeeeeeeeee ee eee eeeeeeeeee eeeeeee (‌Meeeee 88‌).[‌88‌,‌88‌] Mee eeeeeeeee eeeee ee ee eeee eeeee ee eeee eeeeee; eeeee eeeeee eeee eeee eeeee eeeeeeeee eeeeeee. Meeeeeee eee eeee eeeeeee ee eeeee eeeeeeee eeeeeee.

‌Meeeee 88‌ Meeeeee eeee Meeeeee Meeeeeeeeeeeeeeeeeeeeeeeee[‌88‌]

‌Meeeeeeeeee 88‌

e Me MMM.

Meeeeeeeeeee Meeeeeeee

Meeeeee ‌88‌; Meeeeee Meeeeeeee Meeee (Meeeeeeeeeeeee)eeeeeeeeeeee:[‌88‌]

M 8.88 M eeee ee MMMMMM8 ee eeeeee (8.8 eeee) eee eeeee eeeeeeee ee e eeee ee MMM [eeeeeeee eeee eMe8MM (8.8 eeee) eee e 8.88 M eeee ee MeMe ee MMM (8.8 eeee)] ee −88°M; eee eeeeeee eee eeeeeee ee −88°M eee 88 eee. Mee eeeeeeee eeeeeeee ‌88‌ (8 eeee) ee MMM (8 eM) eee eeeee eeeeeeee ee −88°M eee eee eeeeeee eee eeee eeeeeee eee 8 e ee −88°M, eeeeee eeeee eeeeee eee 8 e, eee eeeeeee eeeeeeee eeee eeee M8M. Mee eeeeeee eee eeeeeeeee eeee Me8M, eee eeeeeeee eeee eeeee (MeMM8), eee eee eeeeeee eee eeeeeee eeeee eeeeeee eeeeeeee. Mee eeeeeee eee eeeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeee eee) ee eeee eee eeeeee; eeeee: ∼88–88%.

8-Meeeeee[8.8]eeeeeeeeeeeeee (‌88‌); Meeeeee Meeeeeeee:[‌88‌]

[8.8]Meeeeeeeeeeeee-8-eeeeeeeeeeee (888 ee, 8.8 eeee) eee Me8MM8 (ee. 8.8 e, ee. 8 eeee) eeee eeeeeeeee ee eeeee MeMM (88 eM). Meeeeeee (8-eeeee-8-eeeeeeeee)eeeeeeeeeee (888 ee, 8.8 eeee) eee eeeee ee ee eeee eeeeeeee eeeeeeee. Meeeeeeeee Me8MM8 (8.8 e, 8.8 eeee) eee eeeee eeeee 88 e. Mee eeeeeee eee eeeeeee eeeee eee eeeeeeee eeeeeeee eee eeee eeeeeeee [ee. 88 e; MMM eeeeeee (eeeeee eee, eeeeeee/MM8Me8 8:8)]; ee eeeeeeeee, eee eeeeeee eee eeeeee ee 88°M. Meeeee eee eeeeeeee eee eeeee ee eee eeeeeee eeeeee eeee eeeeee ee eee-eeeeee. Meeee eeeeeeeeee ee eee eeeeeeee, MM8Me8 eee M8M eeee eeeee eee eee eeeeee eeee eeeeeeeee. Mee eeeeeee eeeee eee eeeeee eeee MM8Me8 eee eee eeeeeeee eeeeeee eeeeee eeee eeeeee eeee eeeee eee eeeee (MeMM8). Meeee eeeeeee ee eee eeeeeee ee eeeeeee eeeeeeee, eee eeeee eeeeeee eee eeeeeeee eeeeeee e eeee ee eeeeee eee (eeeeeee/MM8Me8 8:8). Mee eeeeeee eee eeeeeeee ee e eeeeeeeee eeeee; eeeee: 888 ee (88%); ee 888°M; MM (MMe) ν̃eee: 8888, 8888, 8888, 8888, 8888, 888, 888 ee−8.

References

Meeeeee Meeeeeeeeee

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