Studies of the reactions of some benzenalkenyl ethers with benzenselenenyl halides

Abstract

<span style="font-size:16.0pt;mso-bidi-font-size:8.0pt">Intramolecular cyclization of some benzenalkenyl ethers with

<span style="font-size:16.0pt;mso-bidi-font-size:8.0pt">benzenselenenyl halides (PhSeX, X=CI and Br) at different

<span style="font-size:16.0pt;mso-bidi-font-size:8.0pt">temperatures (-78°C, 0°C and room temperature) has been investigated. It has been found that Δ^{<span style="font-size:13.5pt;mso-bidi-font-size:5.5pt">4</span>}<span style="font-size:16.0pt;mso-bidi-font-size:8.0pt">-alkenyl benzyl ethers afford cyclic phenylselenoethers of the tetrahydrofuran and tetrahydropyran type, the ratio of which depends upon the number and position of alkyl substituents at the double bond and at the

<span style="font-size:16.0pt;mso-bidi-font-size:8.0pt">carbinol carbon atom. Δ^{<span style="font-size:14.0pt;mso-bidi-font-size:6.0pt">5</span>}<span style="font-size:16.0pt;mso-bidi-font-size:8.0pt">-Alkenyl benzyl ethers give only six-membered ether rings. The yield of cyclic phenylselenoether products decreases with an increase of the reaction temperature.

<span style="font-size:16.0pt;mso-bidi-font-size:8.0pt;font-family:" times="" new="" roman";="" mso-fareast-font-family:"times="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">PhSeCI is more efficient than PhSeBr for the cyclization reaction.</span></span></span></span></span></span></span>