Science of Synthesis

Krueger, A., Science of Synthesis, (2008) 43, 537.

Instead of cyclopropyl compounds as substrates for coarctate reactions, it is also possible to use enones. After transformation into epoxy ketones and subsequent formation of the respective tosylhydrazone, the fragmentation yields an alkyne and a ketone (‌Scheme 75‌).[‌282‌–‌287‌] Usually the reaction is carried out under acidic (preferred) or basic conditions at room temperature. Although the mechanism of this reaction is related to the rearrangement of cyclopropylcarbenes, the reaction conditions do not favor the formation of carbenes or diazo compounds.[‌263‌] Other mechanistic facts are responsible for the preferred reaction in systems fixed in an endo conformation (similar to the endo preference in cyclopropylcarbene rearrangements). Several examples of the Eschenmoser–Tanabe reaction have been described in the literature. Many of them are cleavages of the A-ring of steroids (see ‌Table 15‌).

‌Meeeee 88‌ Mee Meeeeeeeeee–Meeeee Meeeeeee[‌888‌–‌888‌]

Meee eee eeeeeeee eeeee ee eeeeeeeeee eeeeeeee, eee eeeeee eeeeeeeeeeeee eeeeeee eeeeeeee eeee eee eeeeeeeee ee eee eeeeeeeee eeeeeeeee. Meee eeeeeeeeee ee eeeeeeee ee eee eee ee 8 eeeeeeeeeee ee eeeeeeeee eee eeeeeeee ee eee eeeeeeeee eeeeeeee eeeeeeeee, e.e. ee eeeeeee ee eeeeeee.[‌888‌]

Meeeeeeeee eeeeee eeee ee eeeeeeeeee eeeeee eeee eeeee eeeeeeee, eeeeeee eeeee eeeeeeeee eeee ee eeeeeeeee eeeeee eeee eeee ee eeeeeeeeeeee.[‌888‌] Meeeeeee, eeeeeeeeee eeeeeeeeee eeeeeeee eeeeee ee eeeeeeee ee eee eeeeeeeeeeeee ee eee eeeeeeeeee eeeeeeeeeeeeeee.[‌888‌–‌888‌] Me eeee eeee, e eeeeeeeee eeeee (8,8-eeeeeeeeeeeee)eeeeeeeeeeeeeeeee eeeeeee eeeee ee eee eeeeeee eeeeeeee, e.e. eee-8-eeee (‌888‌) (‌Meeeee 88‌).[‌888‌]

‌Meeeee 88‌ Meeeeeeeeeeee ee (8,8-Meeeeeeeeeeee)eeeeeeeeeeeeeeeeee Me Meee Meeeeee[‌888‌]

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

‌Meeeee 88‌ Meeeeeeeeeeee ee M-Meeeeeeeeeeeeee Me Meee Meeeeee[‌888‌]

‌Meeee 88‌ Meeeeeeeeee ee Meeeeee ee eee Meeeeeeeeee–Meeeee Meeeeeee ee Meeee Meeeeee[‌888‌–‌888‌]

Meeeeeee	Meeeeee	Meeeeeeeee	Meeee (%)	Mee
		MeMMMM8 (8.88 eeeee), eeeeeee/MeMM (8:8), 8°M, 88 eee	88	[‌888‌]
		MeMMMM8 (8.88 eeeee), MM8Me8/MeMM (8:8), 8–88°M, 8 e	88	[‌888‌]
		MeMMMM8 (8.88 eeeee), MM8Me8/MeMM (8:8), 8°M, 88 e, eeee ∼88°M, 8 e	88	[‌888‌]
		MeMMMM8, MM8Me8/MeMM, 8 e	88	[‌888‌]
		MeMMMM8 (8.88 eeeee), MM8Me8/MeMM (8:8), 8°M, 8 e, eeee 88°M, 88 e	88 88–88	[‌888‌] [‌888‌]
		MeMMMM8 (8.88 eeeee), MM8Me8/MeMM (8:8), 8°M, 88 e, eeee MeMM, 88°M, 8 e	88	[‌888‌]
		MeMMMM8 (8.88 eeeee), MeMM, 88 eee	88	[‌888‌]
		MeMMMM8 (8.88 eeeee), MM8Me8/MeMM (8:8), −88°M, 88 e, eeee ∼88°M, 8 e	88	[‌888‌]
		MeMMMM8 (8.88 eeeee), MM8Me8/MeMM (8:8), −88°M, 88 e, eeee ∼88°M, 8 e	88	[‌888‌]
		MeMMMM8 (8.88 eeeee), MM8Me8/MeMM (8:8), −88°M, 88 e, eeee ∼88°M, 8 e	88	[‌888‌]
		MeMMMM8, MeMM, 88°M	88	[‌888‌]
		MMMMM, MM8Me8	88	[‌888‌]
		MeMMMM8, MM8Me8/MeMM (8:8), 8°M, 8 e, eeee ee, 88 eee, eeee MM8•Me8M, ee	88	[‌888‌]
		MeMMMM8, MM8Me8/MeMM (8:8), −88°M, 88 e, eeee ee, 8 e	88	[‌888‌]
		MeMMMM8, MeMM, 888°M, 88 eee, eeee 8°M, 88 e, eeee MeMM8, ee, 8 e	88	[‌888‌]
		8,8-eeeeeeeeeeeeeeeeeeeeee, MMM, −88°M, 88 eee, eeee 8°M, 88 e, eeee eeeeeeee (8 eeeee), ee, 88 eee	88	[‌888‌]
		8,8-eeeeeeeeeeeeeeeeeeeeee, MMM, −88°M, 88 eee, eeee Me8MM8, 88°M, 8 e, eeee 88°M, 8 e	88	[‌888‌]
	MeM≡MM	888°M	88	[‌888‌]
	eMeM≡MM	eeee eeeeeeeee, 888°M	88e	[‌888‌]
		eeeee-eeee eeeeeeeee, 888°M	88e	[‌888‌]
		eeee eeeeeeeee, 888°M	88e	[‌888‌]
		888–888°M, 88–88 eee, eeee eeeeeee (88 Meee)	88e	[‌888‌]
		888–888°M, 88–88 eee, eeee eeeeeee (88 Meee)	88	[‌888‌]
		888–888°M, 88–88 eee, eeee eeeeeee (88 Meee)	88e	[‌888‌]
		eeeeeee, ∼88°M, eeee Meeeeeeee (888–888°M/88 Meee)	88	[‌888‌]
		eeeeeee, 888°M, 8 e	88	[‌888‌]
		888–888°M, ∼888 Meee, 88 eee	88	[‌888‌]
		MeMMMM8, MM8Me8/MeMM (8:8), ee, eeeeeeeee	88	[‌888‌]

e Meeeeeeeee ee MM.

e Meee eeeeeee.

Meeeeeeeeeee Meeeeeeee

Mee-8-eeee (‌888‌) eee e (8,8-Meeeeeeeeeeee)eeeeeeeeeeeeeeeee:[‌888‌]

Me −88°M, 8,8-eeeeeeeeeeeeeeeeee (8.888 e, 8 eeee) eee eeeee ee e eeee ee (8,8-eeeeeeeeeeeee)eeeeeeeeeeeeeeeee (8.888 e, 8.8 eeee) ee MMM (88 eM). Meeee eeeeeeee eee eeeeeee eee 88 eee ee −88 ee −88°M, ee eee eeeeee ee −88°M eee eeee ee eeee eeeeeeeeeee eee 88 eee. Meeee eeeeeeee eee eeeeeee ee 8°M, ee eee eeeee (MeMM8) eee eeeeeeee (<8°M). Mee eeeeeeee eee eeeeeee eee 8 eee, eee eeee e eeee ee eeeeeeee eee eeeee, eeee eeeeeeeee eeeeeeee. Meeeeee eeee ee eeeeeeee eee eeeee eeeee 8 eee, eeeeeee ee eeeeee eee eeeeeeeee. Me eee eeee eeee, eee eeeeeee eeeeee eeee eeeeee. Meeee 8 eee, eee eeeeeeeee ee eee eeeeeeee (8.88 e, 8 eeee) eee eeeee eee eee eeeeeee eee eeeeeee eee 8 eee. Meeee eeeeeeeeee eeeeeee Meeeee, eee eeeeeeee eee eeeeeee ee ee eee 88 eee eeee eeeeeeeeee MeMM8•8M8M (8 e). Meeee eeeeeeeeee, eee eeeeeeee eeeeeeeeee ee eee eeeeeee eeee eeeeeeeee ee ∼88°M/8.88 Meee eeee e eeee eeeeee eeee MMM (88 eM) eee 8,8-eeeeeeeeeeeeeeeeeeeeee (8.888 e, 8 eeee). Mee eeeeeeeee eeeeeee eee eeee ee 88–88°M eee 88 e. Mee eeeeeee eee eeee eeeeeeeeee eee eee eeeeeee eee eeeeeeee ee eeeeeeeeeee MMM (eeeeee eee, MM8Me8) ee eeee eeeeee eeeeeeee; eeeee: 8.888 e (88%); ee 88–88°M.

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

Me e eeee ee 8,8-eeeeeeeeeeeeeeeeee (8.88 e, 88 eeee) ee eeeeeee (888 eM) (MMMMMMM: eeeeeeeeee) eee eeeee eeeee-8-eeeee-8,8-eeeeeeeeeeeeeeeee (88.88 e, 88.8 eeee). Meeee eeeeeeee eee e eeeee eeee, eee eeeeeeeee eeeee eeee eeeeee eeeeee eee eeeeee. Meeee 8 e, eee eeeeeee eee eeeeeee ee eeeeee eeeeeeeeeee (<88°M). Mee eeeee eeeeeee (88.8 e) eee eeeeeeeee ee eeeeeee eeeeeeeee (88 eM). Meee eeee eee eeeeeee eeee 8 e (eeeee, 88 Meee, eeeeeeeee eeeeeeee) eeee eee eeeeeeeee (888–888°M) eeeee ee e eeeeeeeeeeeee eeeeeeeee (888-eM eee-eeeeee eeeee, eeeee eeeeeeeeeeee eeee, eeeeeeeee, eee-eeeeee eeeeeeee, eee eee eee/eMeMM eeeeee eeee). Meeeeeeeeee, eeeeeeee eeeeeeeeeeeee eeee eeeee eee eee eeeeeeeeeeeee eeeeeee eeeeee eeeeeeeee eeee eee eeeeeeee. Mee eeeeeeeeee ee eee eeeeeeee eee eeeeeeeee eee eeeeee ee 888–888°M eee e eeeee eeee eeeee eee eeeeeeeee eeeeee. Meeee eeeeeeeeeeeeee eeeee e Meeeeee eeeeee (eeeeeee eeeee eee eeee eeeeeeeee), eee eeeeeee eee eeeeeeee (8.88 e); eeeeeee eeeeeee (8.88 e) eee eeeeeeee ee eeeeeeeeeeee ee eee eeee eeeeeee; eeeee: 8.88 e (88%); ee 88–88°M/88 Meee; eM88 8.8888.

8,8-Meeeeeeeeeee-8-ee-8-eee (‌888‌): [‌888‌]

8,8-Meeee-8,8,8-eeeeeeeeeeeeeeeeeee-8-eee (‌888‌, eeeeeeeeee eeeeeee; 8.8 e, 88 eeee) eee eeeeeeeee ee MM8Me8/MeMM (8:8; 888 eM) eee MeMMMM8 (8.888 e, 88.8 eeee) ee MM8Me8/MeMM (8:8; 888 eM) eee eeeee ee 8°M. Meeee eeeeeeee ee 8°M eee 8 e, eee eeeeeee eee eeeeeee eeeeeeeee ee ee (ee. 888 eM M8 eee eeeeeee). Mee eeeeee eeee eee eeeeee eeee eee eeeee eee eeeeeeeee eeee Me8M. Mee eeeeeee eeeeeee eee eeeeee eeee eee. MeMMM8 eeee eee eeeee eee eeee eeeee (Me8MM8). Meeee eeeeeeee eeeeeee ee eee eeeeeee, eee eeeee eeeeeee eee eeeeeeee (8.8 e). M eeeeeee ee eeee eeeeeee (8.88 e) eee eeeeeeeeeeeeeee (eeeeee eee, eeeeeee/Me8M 8:8); eeeee: 8.88 e (88%); ee 88–88°M/88 Meee; eM88 8.8888.

References

Meeeeee Meeeeeeeeee

• 8.Meeeee-Meee, (8888) 8/8e, 888.