Table 3.

Double-Michael Annulations of Substituted Allenoates^a

entry	X, Y	R1,R2	product	yield (%)b
				PMe3	DMAP
1	O,NTs	Ph, H (2c)	4i	83
2	O,NTs	Bn, H (2d)	4j	61	77
3	O,NTs	t-Bu, H (2e)	4k	69	51
4	O,S	Me,H	4l	74	76
5	O,S	Ph,H	4m	86
6	O,S	Bn,H	4n	65	89
7	O,S	t-Bu, H	4o	58	48
8	O,O	Me,H	4p	70	68
9	O,O	Ph,H	4q	77
10	O,O	Bn,H	4r	89	74
11	O,O	t-Bu, H	4s	82	68
12	O,O	H, Me (2f)	4t	89
13	O,O	H, Bn (2g)	4u	86
14	O,O	H, CH2CO2Et(2h)	4v	80
15c	O,NTs	H,Me	4w	81d
16c	O,NTs	H,Bn	4x	73d
17c	O,NTs	H, CH2CO2Et	4y	84d

^aReactions were performed using 0.4 mmol of 1 and 1.35 equiv of 2.

^bIsolated yield.

^cNaOAc (50 mol %) was added.

^dDiastereoisomeric ratio determined using ¹H NMR spectroscopy. Diastereomeric ratios 1:1, 2:1, and 1.2:1 for 4w, 4x, and 4y, respectively.