Science of Synthesis

Kostikov, R. R.; Khlebnikov, A. F.; Sokolov, V. V., Science of Synthesis, (2010) 47, 826.

Alkyl phenyl selenoxides ‌91‌ upon heating undergo syn elimination to give alkenes (‌Scheme 36‌).[‌195‌] This has two principal advantages over the analogous elimination from sulfoxides: first, the reaction occurs at temperatures approximately 100°C lower and, second, the oxidation of selenides to selenoxides can be carried out with inexpensive oxidizing agents such as hydrogen peroxide, peracetic acid, or tert-butyl hydroperoxide. Substituent effects and stereochemistry are similar to those observed for sulfoxide eliminations, including faster rates for compounds forming conjugated alkenes (dienes, styrenes, enones) and aryl selenoxides bearing electron-withdrawing substituents. The formation of cyclohexene from cyclohexyl phenyl selenoxide proceeds more slowly than that of cyclopentene from cyclopentyl phenyl selenoxide.[‌196‌] The preparation of (R)-3-methylnon-1-ene (‌92‌) is typical for that of alkenes obtained by thermolytic elimination from alkyl selenoxides.[‌197‌]

‌Meeeee 88‌ Meeeeeeee ee Meeeeee eeee Meeee Meeeeeeeeee[‌888‌,‌888‌]

Meeeeeeeeeee Meeeeeeee

(M)-8-Meeeeeeee-8-eee (‌88‌); Meeeeee Meeeeeeee:[‌888‌]

(M)-(−)-8-Meeee-8-eeeeeeeeeeee (8.8 e, 88.8 eeee) eee eeeee ee e eeee ee eeeeeeee eeeeeeeeee (8 e, 88.8 eeee) ee MeMM (88 eM), eeeee eee eeeeeeee eeee MeMM8 (8 e, 88 eeee) eeeee ee eeee M8 eeeeeee eee, eee eeeeee eeeee eeeeee eee 8 e. Meeee eeeeeee ee 8°M, 88% M8M8 (88 eM) eee eeeee, eee eee eeeeeee eee eeeeee ee 88°M eee 8 e. Meeeee eeee eeeeeee eeeeeeee ee eeeeeeeeeeee (88–888°M/888 Meee) eeee eee eeeeeeee eeeeee; eeeee: 8.8 e (88%); 8M MMM (888 MMe, MMMe8, δ): 8.88 (e, M = 8 Me, 8M, M8-MM8), 8.88 (e, M = 8 Me, 8M, M8-MM8), 8.88–8.88 (e, 8M, =MM8), 8.88–8.88 (e, 8M, =MM); MM (88 eM) e/e (eeeeeeee eeeeeeeee): 888 (8%), 888 (88%), 88 (8%), 88 (88%), 88 (888%).

References