DA reaction between 2,3-dimethylbutadiene 7 and various dienophiles.

Entrya	5	Conv.b (%)	8 yieldc (%)
1	5a	82	75
2	5b	100	82
3	5c	80	73
4	5d	32	27
5	5e	7	5
6	5f	16	16
7d	5f	34	27
8	5g	61	60
9	5h	100	92

^aReaction conditions: 7 (0.45 M), 5 (0.15 M), C₆ and TrX (0.039 M) in 1.1 mL of water-saturated CDCl₃, at rt for 16 h.

^bDetermined by ¹H NMR analysis of the crude reaction mixture according to literature data.^21a,b,26

^cIsolated yield.

^dThe reaction was carried out at 50 °C.