Pyrylium Salts of g-Thiapyrones --- A Simple Step to Phosphono-phosphino Substituted Pyridines and Pyridinium Salts
摘要:
The phosphono-phoshino substituted gamma-thiapyrones (1/2) are converted to pyrylium salts (3/4) with trimethyloxonium tetrafluoroborate (5) under mild conditions. Reactions of the pyrylium salts (3/4) with ammonia and primary amines (10) lead to phosphono-phosphino pyridines (6/7) and pyridinium salts (8/9).