I_2/离子液体作为可回收均相催化剂在微波条件下高效制备全乙酰糖(英文)

以可回收的I2/PEG400型离子液体(I2/IL400)为催化体系,发展了一种高效、实用的合成全乙酰糖衍生物的方法.结果表明,以糖与乙酸酐为原料,在微波辐射、无溶剂条件以及I2/IL400体系中,数分钟之内可以非常高的产率(90%–99%)和数十毫摩尔规模(50.0 mmol)制备出全乙酰糖.通过简单的甲苯萃取,可以从I2/IL400体系中分离出全乙酰糖,I2/IL400体系可循环使用6次,且产率均在90%以上.当反应规模扩大到50.0 mmol时,该体系依然能高效快速地催化糖的全乙酰化,并且可以循环使用5次,产率依然维持在90%左右.

I2/ionic liquid as a highly efficient catalyst for per-O-acetylation of sugar under microwave irradiation

A practical and highly efficient approach was developed to synthesize peracetylated sugar deriva‐tives using a recyclable iodine/PEG400‐based ionic liquid catalyst (I2/IL). The peracetylated sugars were readily obtained in a few minutes in excellent yields (90%?99%, 13 examples) on a mul‐ti‐gram scale (50.0 mmol) by the reaction of sugar and acetic anhydride under microwave irradia‐tion in the absence of a volatile organic solvent. The desired product was easily obtained by simple extraction with toluene from the reaction mixture, and I2/ILs can be readily recovered and reused at least six times without obvious loss in the yield. When the scale of the per‐O‐acetylation reaction was increased to 50.0 mmol, the desired product was still obtained in 90%yield after five recycles.