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. 2024 Nov 20;14(50):37216–37226. doi: 10.1039/d4ra07318e

Optimization of direct glycosylation reaction conditions.


Entry	Silylation conditions	Solvent/catalyst	Höffer's sugar (eq.)	Temp. (°C)	Anomeric ratio (crude) (β/α)^a	Isolated yield (%) (β-anomer)
1	BSTFA (excess)^a acetonitrile	CH₂Cl₂	1.1	RT	N/A	N/A
1	BSTFA (excess)^a acetonitrile	SnCl₄ (1.0 eq.)	1.1	RT	N/A	N/A
2	Et₃N (1.6 eq.)	ClCH₂CH₂Cl	0.85	−30	9 : 1	48
2	TMS-Cl (1.2 eq.) benzene	SnCl₄ (3.0 eq.)	0.85	−30	9 : 1	48
3	Et₃N (2.0 eq.)	ClCH₂CH₂Cl	0.85	−30	9 : 1	51
3	TMS-Cl (1.4 eq.) benzene	SnCl₄ (3.0 eq.)	0.85	−30	9 : 1	51
4	Et₃N (1.6 eq.) TMS-Cl (1.2 eq.) benzene	ClCH₂CH₂Cl	1.2	−30	5 : 1	28
4	Et₃N (1.6 eq.) TMS-Cl (1.2 eq.) benzene	SnCl₄ (3.0 eq.)	1.2	−30	5 : 1	28
5	Et₃N (1.6 eq.) TMS-Cl (1.2 eq.) benzene	ClCH₂CH₂Cl	0.85	0	10 : 1	60
5	Et₃N (1.6 eq.) TMS-Cl (1.2 eq.) benzene	SnCl₄ (3.0 eq.)	0.85	0	10 : 1	60

^a

Entry 1 as per Cristalli et al.¹⁰

^b

Crude anomeric ratio's measured by H NMR.