Table 3.

The reactions of primary amines with triethyl orthoformate and diethyl phosphite.

Entry	Y	DEP (equiv)	T (°C)	t (h)	Conversion (%)a	Product composition (%)a			Yield of 3 (%)c
						3	by-productsb
							4	5
1	Bu	2	125	2	91	81	19	0	–
2	Bu	2	150	0.5	100	78	15	7	61 (3a)
3	Bu	3.5	125	1	75	100	0	0	–
4	Bu	3.5	125	1.5	90	78	22	0	–
5	c-Hex	2	125	2	76	83	17	0	–
6	c-Hex	2	150	0.5	100	88	10	2	68 (3b)
7	c-Hex	3.5	125	1	63	100	0	0	–
8	c-Hex	3.5	125	1.5	83	86	14	0	–
9	Ph	2	125	2	68	56d	0	0	36 (3c)
10	Ph	2	150	1	90	70d	0	0	52 (3c)
11	Ph	3	125	1	100	100	0	0	82 (3c)

^aOn the basis of GC (entries 1–8) or on the basis of HPLC (entries 9–11). ^bThe by-products identified:

^cIsolated yield. ^dThe following intermediates were also formed based on LC–MS: