Synthesis of 1,4-dienes and α-alkoxystyrene derivatives via allyl- and benzylboronation of acetylenic compounds

The hydrometallation, carbometallation, and metallometallation of heteroalkynes

“…However, with simple terminal alkynes allylmetallation is complicated by side-reactions such as hydrogen abstraction which accompanies the allylzincation of terminal alkynes;' 7 s and allylmetallation of internal alkynes fails altogether in the absence of electron-donating groups such as alkoxy substitutents. A case in point is the cis-addition of triallylborane 34 to 1-ethoxyethyne (Scheme 15) 58…”