Convenient method for the preparation of 1-phenylthio-3-alken-1-ynes and 4-hydroxy-1-phenylthio-1,2-alkadienes from a common precursor

✍ Scribed by Atsushi Ogawa; Kazunari Sakagami; Akiko Shima; Hitoshi Suzuki; Satsuki Komiya; Yoshinori Katano; Oyo Mitsunobu

• Publisher: Elsevier Science
• Year: 2002
• Tongue: French
• Weight: 75 KB
• Volume: 43
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(02)01380-1

✦ Synopsis

Hydroxy-1-phenylthio-2-alkynes (5) reacted with dihydropyran to afford the corresponding 4-tetrahydropyranyloxy derivatives which, on treatment with KHMDS, gave a mixture of (E)-and (Z)-1-phenylthio-3-alken-1-ynes, with the former predominant. When MeLi was used in the place of KHMDS, the (Z)-isomers were formed in preference to the (E)-isomers. Further treatment of the mixture with a base converted the (Z)-isomers into (E)-isomers. On the other hand, the reaction of 5 with KHMDS gave the corresponding 4-hydroxy-1-phenythio-1,2-alkadienes.