Crystal form of BTK kinase inhibitor intermediate and preparation method thereof

The invention relates to a crystal form of a BTK kinase inhibitor intermediate and a preparation method thereof, and belongs to the technical field of medicines. The crystal form is a crystal form IV of (R)-1-(1-(t-butyloxyacyl) pyrrolidine-3-yl)-3-cyano-4-(4-(2, 6-difluorophenoxy) phenyl)-1H-pyrrole-2-ethyl formate, and the crystal form IV of (R)-1-(1-(t-butyloxyacyl) pyrrolidine-3-yl)-3-cyano-4-(4-(2, 6-difluorophenoxy) phenyl The (R)-1-(1-(tert-butoxyacyl) pyrrolidine-3-yl)-3-cyano-4-(4-(2, 6-difluorophenoxy) phenyl)-1H-pyrrole-2-ethyl formate crystal form IV obtained by the invention has good chemical stability and crystal form stability, is beneficial to storage and transportation, can highly purify an intermediate to obtain a sample with the purity of 99.82% or above, and has good application prospects. The compound has important significance on quality control of a BTK kinase inhibitor (R)-4-amino-1-(1-(butyl-2-alkynol) pyrrolidine-3-yl)-3-(4-(2, 6-difluorophenoxy) phenyl)-1, 6-dihydro-7H-pyrrolo [2, 3