Table 1.

Yields of intermediates (3, 4) and end products 5 obtained according to Scheme 1

Entry	R1	R2	X	Path	Yield (%)a
					3	4	5
a	C6H5	CH3	O	A	87	–	93
b	CH3	H	O	A	85	–	91
c	CH3	CH3	O	A	89	–	95
d	CH3	C6H5	O	A	90	–	93
				B	–	95	94
e	C6H5	C6H5	O	A	84	–	86
				B	–	93	88
f	CH3	CH3	S	B	–	–	87
g	CH3	C6H5	S	B	–	–	81

^aExcept for entries f and g, yields of 5 are based on the corresponding intermediate 3 or 4.