Table 2. Scope of the 3′-functionalization of nucleosides.

Entry	Nucleoside	Electrophile	Product	Yield e	3′ : 5′ g
1 a				92	98 : 2
2 a	(1b) R = Cl	4	(2b) R = Cl	89	98 : 2
3 a	(1c) R = –CCH	4	(2c) R = –CCH	74	92 : 8
4 a	(1d) R = N3	4	(2d) R = N3	62	91 : 9
5 a	(1e) R = CN	4	(2e) R = CN	58	97 : 3
6		4		84	ND
7		4		85 f	ND
8 a , b		4		57	93 : 7
9	5			71	96 : 4
10 c	5			59 (68 brsm) d	99 : 1

^aAnions are expected to be formed and serve as the structures modelled in the conformational analysis.

^b2 equivalents of DBU used and temperature lowered to –15 °C.

^cTemperature lowered to –15 °C.

^dBased on recovered starting material (brsm).

^eIsolated yields of pure 3′-phosphorated product and major p-epimer.

^fAssay yield.

^g3′ : 5′ selectivity determined by HPLC or UPLC, if labelled ND we were unable to resolve or detect the 5′-product the peaks by LC.