Table 2. Solid-Phase Synthesis of N_PST Dimers.

	condensation reaction conditions
entry	monomer	base	product	chemoselectivity (PO:PS)a	HPLC yield (%)b
1	5a	quinoline	dAPST (10)	2:98	95
2	5a		dAPST (10)	3:97	70
3	5c	quinoline	dCPST (12)	2:98	96
4	5c		dCPST (12)	2:98	94
5	5g	quinoline	dGPST (14)	1:>99	88
6	5g		dGPST (14)	1:>99	91
7c	5g		dGPST (14)	1:>99	93

^aDetermined by RP-HPLC: area ratio of N_PST and N_POT.

^bDetermined by RP-HPLC: area ratio of N_PST/(N_PST + N_POT + T).

^c0.2 M monomer and 0.5 M condensing reagent were used.