Va. Glushkov et Yv. Shklyaev, OXIRANES IN THE RITTER REACTION - SYNTHESIS OF 6,7-(OR 5,8-)DIMETHOXY-3,4-DIHYDROISOQUINOLINES BY A TANDEM ALKYLATION-CYCLIZATION PROCEDURE, Mendeleev communications, (1), 1998, pp. 17-18
Treatment of 1,2-(or 1,4)-dimethoxybenzene with isobutylene oxide and
an appropriate nitrile RCN in concentrated sulfuric acid leads to 1-R-
6,7-(or -)dimethoxy-3,3-dimethyl-3,4-dihydroisoquinolines.