Montmorillonite clay catalyzed alkylation of pyrroles and indoles with cyclic hemi-acetals

Cyclic hemiacetals such as 2-deoxy-d-ribose and 2-deoxy-d-glucose react smoothly with pyrroles and indoles on the surface of montmorillonite KSF clay under extremely mild reaction conditions to afford optically active di-pyrrolyl and bis-indolyl alkanols in good yields with high selectivity.