Table 2. Reaction of Glycals 9a–d and 11a–c with Model Glycosyide Acceptors 2a, 2e, or 2g.

entry		R1	R2	R3	product	time (h)	yield (%)a	α/βb
1	9a	Bn	Bn	Bn	10a	1	88d,e	21:1
2	9a	Bn	Bn	Bn	10c	1	94	26:1
3	9a	Bn	Bn	Bn	10e	2	84	30:1
4	9a	Bn	Bn	Bn	10g	7	62	25:1
5	9a	Bn	Bn	Bn	10h	7	68	20:1
6	9b	TBS	TBS	TBS	11b	1	92	30:1
7	9c	MOM	MOM	MOM	11c	1	71	20:1
8	9d	Si(tBu)2		MOM	11d	1	82	20:1
9	11a	Bn	Bn	Bn	12ac	17	54	30:1
10	11b	O[Si(i-Pr)2]2		Bn	12b	17	78	30:1
11	11c	O[Si(i-Pr)2]2		TIPS	12c	17	75	30:1
12	11c	O[Si(i-Pr)2]2		TIPS	13	17	86	30:1
13	11c	O[Si(i-Pr)2]2		TIPS	14	17	64	20:1

^aIsolated yield.

^bDetermined by ¹H NMR.

^c10% Ferrier product 12a′ also isolated.

^dReaction did not proceed in the absence of catalyst.

^eReaction with BF₃.OEt₂ afforded 10a (<35%) and a mixture of products and starting material.