Reactions of Allenylic Tin Reagents to<i>N</i>-Alkoxycarbonyl-isoquinolinium and -quinolinium Salts. Effective Introduction of 2-Alkynylic Groups to Isoquinoline and Quinoline Systems
with isoquinoline in the presence of chloroformate esters as acylating agents give 2-alkoxycarbonyl-1-(2-alkynyl)-1,2-dihydroisoquinolines in good to excellent yields. Similarly, the reactions with quinoline give 1-alkoxycarbonyl-2-(2-alkynyl)-1,2-dihydroquinolines exclusively.