Organocatalytic Decarboxylative Borylation of Cyclopropane N-Hydroxyphthalimide Esters
Yevhen Krokhmaliuk1,2, Ihor Kleban1,3, Yuliya V Rassukana3
1Enamine Ltd. (www.enamine.net), Winston Churchill Street 78, Kyïv 02094, Ukraine.
Abstract:
A convenient protocol for the two-step organocatalytic decarboxylative borylation of 1,1-disubstituted, 1,2-disubstituted, and bicyclic cyclopropane carboxylic acids via the corresponding N-hydroxyphthalimide esters is described, using tert-butyl or ethyl isonicotinate as an inexpensive and readily available catalyst. The scope of the method was demonstrated, being limited mainly by electron-poor substrates. The reaction sequence showed good scalability (up to 51.5 g) and excellent trans diastereoselectivity (for the case of 1,2-disubstituted substrates). Therefore, the proposed approach is a very promising alternative to other existing (i.e., metal-catalyzed) methods for borodecarboxylation.
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