Hydroalumination of phenylthioacetylenes. Synthesis and reactions of (Z)- and (E)-1-butyltelluro-1-phenylthio-1-alkenes

✍ Scribed by Miguel J Dabdoub; Palimécio G Guerrero Jr.

• Publisher: Elsevier Science
• Year: 2001
• Tongue: French
• Weight: 435 KB
• Volume: 42
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)01511-8

✦ Synopsis

Hydroalumination of phenylthioacetylenes with the Zweifel's reagent as reducing agent followed by the addition of C 4 H 9 TeBr afforded (Z)-telluro(thio)ketene acetals (Z >80-93%). The (E)-isomers were obtained with 100% stereoselectivity by reduction of thioacetylenes with DIBAL-H, followed by the addition of n-BuLi and subsequent treatment with C 4 H 9 TeBr. Reaction of the (E)-telluro(thio)ketene acetals with n-BuLi followed by the addition of valeraldehyde afforded the (Z)-phenylthio allylic alcohol as the main product and traces of the (E)-isomer, while the mixture of (Z)-and (E)-telluro(thio)ketene acetals under similar reaction conditions gave the (E)-phenylthio allylic alcohol exclusively.