Table 1.

Structures and yields of compounds A and B ^a.

Compound	R1	R2	R3	R4	A, %	B, %
1	(CH2)3CH3	CH2CH3	H	H	88	93
2	(CH2)3CH3	CH2CH3	Cl	H	70	92
3	(CH2)3CH3	CH2CH3	H	CH3	72	91
4	(CH2)3CH3	CH2CH3	H	OCH3	70	89
5	(CH2)3CH3	C(CH3)3	H	H	70	88
6	CH2Ph	CH2CH3	H	H	78	78
7	CH2Ph	C(CH3)3	H	H	80	78
8	Ph	CH2CH3	H	H	73	94
9	4-MeC6H4	CH2CH3	H	H	72	92
10	4-MeOC6H4	CH2CH3	H	H	76	91

^a Compounds 1, 6, 7 and 8 were known in the literature [38].