PTC transesterification in basic medium

The microwave-assisted PTC transesterification of several carbohydrates in basic medium with methyl benzoate or laurate has been studied [96], Small amounts of DMF were necessary to provide good yields within 15 min at 160 °C. Rate enhancements were compared to conventional heating (A) under the same conditions and specific microwave activation was mostly seen when the less reactive fatty compounds were involved (Eq. (44) and Tab. 3.19) 

The reactive species under these conditions consist of tight ion pairs involving the alkoxide anion from the carbohydrate (charge localized anion). The less reactive long chain methyl laurate leads to a later TS along the reaction coordinates and the magnitude of the microwave effect is therefore increased. 

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