Table 3.

Tetrabutylammonium-Templated Norrish-Yang Cyclization.

Entry	Substrate[a]	X =	Solvent	NBu4F (equiv)	Conv.[b] (%)	d.r. (55: 56)
1	54a	H	PhCF3	0	17 [c]	0:100 [c]
2				5	93 [c]	93:7 [c]
3			MeCN	0	35 [c]	17:83 [c]
4				5	96 [c]	84:16 [c]
5	54b	Me	MeCN	0	35	20:80
6				5	84	93:7
7	54c	OMe	MeCN	0	70	11:89
8				5	99	94:6
9	54d	CF3	MeCN	0	33	23:77
10				5	6	59:41

^[a]See the substrate structure and substitution pattern in Scheme 16.

^[b]Conversion of 54 after 24 hours.

^[c]After 10 hours.