“…For 13 C NMR, chemical shifts were reported relative to CHCl 3 (77.00 ppm for 13 C NMR) as an internal reference. 2-Methylene-3,4-dihydro-2 H -naphthalen-1-one ( 1a ), 2-methylenecyclohexanone ( 1f ), 2-methylenecyclopentanone ( 1g ), 1,3-bibenzyl-5-methylenehydantoin ( 1j ), ethyl 2,3-butadienoate ( 2 ), tert -butyl 2,3-butadienoate ( 5 ), and tert -butyl 2-butynoate ( 8 ) were prepared by the reported methods.…”