Nature Communications

Table 1 Selected optimization^a.

From: Enyne diketones as substrate in asymmetric Nazarov cyclization for construction of chiral allene cyclopentenones


entry	diazo	variation from conditions A	4 (yield, %)^b
1	1a	none	79
2	1b	none	68
3	1c	none	55
4	1d	none	64
5	1e	none	25
6	1 f	none	52
7	1a	toluene instead of hexane	54
8	1a	CH₂Cl₂ instead of hexane	31
9	1a	Rh₂(esp)₄ instead of Rh₂(OAc)₄	65
10	1a	Rh₂(TFA)₄ instead of Rh₂(OAc)₄	63
11	1a	SiO₂ instead of MgO, 24 h	43

^aMethod A: 1 (0.3 mmol, 1.5 eq.), 2a (0.2 mmol, 1eq.) and Rh₂(OAc)₄ (2 mol%) in hexane (2 mL) stirred at rt. for 12 h under N₂. Then, to the solution were added MgO (200 mg, 50 eq.), CH₂Cl₂ (5 mL) and stirred at 40 ^oC for another 3 h. ^bIsolated yield, dr > 19:1 (determined by ¹H NMR analysis).

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