Cyanuric chloride/sodium borohydride: a new reagent combination for reductive opening of 4,6-benzylidene acetals of carbohydrates to primary alcohols

• First report of benzylidine acetals’ reductive opening towards 6-OH using cyanuric chloride/NaBH4 reagent system.
• Inexpensive reagent, mild reaction condition, high yield with broad functional group tolerance.
• High regioselectivity of reagent system.
• Application to both carbohydrate and non-carbohydrate systems.

In the first such example, NaBH4 in combination with cyanuric chloride (TCT) has been used to obtain 6-hydroxy-4-benzyl ether derivatives from 4,6-benzylidene acetals of carbohydrates. The nature of hydride donor determines the regioselectivity of acetal opening. High regioselectivity, scope for using a broad range of substrates, functional group tolerance, mild reaction conditions, easy handling process, inexpensive reagents and wide application mark the benefits of the newly developed reagent system.

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