Synthesis and Reactions of Lactam Sulfonium Salts with a Sulfonio Bridgehead. II. 1,1a,4,5,6-Pentahydro-6-oxo-2H-thiopyrano(1,6-d)-4,1-benzothiazepinium Perchlorates.
Synthesis and Reactions of Lactam Sulfonium Salts with a Sulfonio Bridgehead. II. 1,1a,4,5,6-Pentahydro-6-oxo-2H-thiopyrano(1,6-d)-4,1-benzothiazepinium Perchlorates.
Benzothiazinone (1) was chlorinated with N-chlorosuccinimide and subsequently submitted to [2++4] cycloaddition with 1,3-dienes in the presence of silver perchlorate to afford cyclic sulfonium salts (3). Reactions of 3 with sodium borohydride or sodium hydride provided 4-vinyltetrahydro-3,6-epithiobenzazocine derivatives (9) in good yields.
Kataoka Tadashi, Nakamura Yoshihide, Matsumoto Harutoshi, Iwama Tetsuo, S+, Heterocycles, 38 (1994) N 8, S 1733-1736