Functionalized Cyclobutanes via Heck Cyclization Anna Innitzer Lothar Brecker Johann Mulzer 10.1021/ol701697r.s003 https://acs.figshare.com/articles/journal_contribution/Functionalized_Cyclobutanes_via_Heck_Cyclization/2978992 Heck-type 4<i>-exo-trig</i> cyclization of linear 2-enol triflate-1,5-hexadienes provides functionalized methylene cyclobutanes. Intramolecular palladium coordination can initiate β-hydride elimination leading to 1,2-dimethylene cyclobutane derivatives, which are obtained with high selectivity if substrates having a geminal diphenyl group at C<sub>α</sub> are used. In parallel, formal 5<i>-endo-trig</i> cyclization and β-hydride elimination form 1-methylene cyclopent-2-en derivatives. 2007-10-25 00:00:00 derivative C α dimethylene selectivity hydride geminal diphenyl group cyclization Intramolecular palladium coordination Functionalized Cyclobutanes cyclopent Heck elimination functionalized methylene cyclobutanes triflate substrate enol