Table 3.

Intermolecular reactions of alkyl azides with aldehydes.

entry	R1	R2	acid	compds 6 and 7	yield, %a
					6	7
1	Ph	PhCH2	TFA	a	trace	trace
2	Ph	PhCH2	TiCl4	a	21	10
3	Ph	n-hex	TFA	b	trace	trace
4	Ph	n-hex	TiCl4	b	16	10
5	Ph	Ph(CH3)CH	TFA	c	trace	trace
6	Ph	Ph(CH3)CH	TiCl4	c	33b	11b
7	PhCH2	PhCH2	TFA	d	16	16
8	PhCH2	PhCH2	TiCl4	d	22	19
9	PhCH2	n-hex	TFA	e	9	9
10	PhCH2	n-hex	TiCl4	e	45	39
11	PhCH2	Ph(CH3)CH	TFA	f	13	5
12	PhCH2	Ph(CH3)CH	TiCl4	f	20	30
13	CH3(CH2)3CH2	PhCH2	TFA	g	19	13
14	CH3(CH2)3CH2	PhCH2	TiCl4	g	29	26
15	CH3(CH2)3CH2	n-hex	TFA	h	28	12
16	CH3(CH2)3CH2	n-hex	TiCl4	h	37	26
17	CH3(CH2)3CH2	Ph(CH3)CH	TFA	i	23	8
18	CH3(CH2)3CH2	Ph(CH3)CH	TiCl4	i	35	27

^aIsolated products, unless otherwise noted.

^bInseparable mixture. Yields estimated from ¹H NMR.