Table 2.

Zinc Triflate-Catalyzed Mukaiyama-Michael Reactions of 1 with Representative Enones^a

entry		enone 5	prduct 6	yieldb, %
1	a			96
2	b			84
3	c			94
4c	d			99
5d	e			68
6e	f			74
7d,f	g			71
8	h			88
9	i			92
10	j			99

^aVinyldiazoacetate 1 (0.75 mmol) was added to a solution of enone 5 (0.5 mmol) and zinc triflate (0.015 mmol) in CH₂Cl₂ (2 mL). The solution was stirred at 0°C and then allowed to warm to room temperature. After 16 hours, the crude reaction mixture was concentrated and then hydrolyzed with 1:5 4N HCl/THF at 0°C. See Supporting Information for details

^bYield of isolated 6 following column chromatography.

^cThe product was isolated as two diastereomers in 3:1 ratio.

^dReaction time was 36 hours.

^eTwo equivalents of 1 was used, 62% yield with 1.5 equiv. of 1; 71% yield with 0.5 mol % of catalyst.

^fReaction was performed in 1 mL CH₂Cl_2, and the concentration of enone 5g was 0.5 M; 78% yield with 0.5 mol % catalyst.