Tetrahedron Letters

An acid-free Pictet–Spengler reaction using deep eutectic solvents (DES)

S Handy, M Wright

Index: Handy, Scott; Wright, Matthew Tetrahedron Letters, 2014 , vol. 55, # 23 p. 3440 - 3442

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Citation Number: 11

Abstract

Abstract Deep eutectic solvents (such as the combination of either urea or glycerol with choline chloride) are effective solvents/organocatalysts for Pictet–Spengler condensations to form carbolines. The reaction conditions are quite mild and do not require additional Bronsted or Lewis acid catalyst. Given the inexpensive, non-toxic, and recyclable nature of the DES, these reaction conditions are simple and highly environmentally friendly.