1: (EtO)2P(O)CH2CC-TMS With sodium hexamethyldisilazane in tetrahydrofuran T=-10°C; Horner-Wadsworth-Emmons olefination; 1 h; Inert atmosphere; 2: 4-(2,6,6-trimethyl-1-cyclohexenyl-1-yl)-3-buten-2-one in tetrahydrofuran T=0°C; Horner-Wadsworth-Emmons olefination; Inert atmosphere; optical yield given as percent de;