1: 1-phenyl-propan-1-one With di-n-butylboryl trifluoromethanesulfonate; N-ethyl-N,N-diisopropylamine in dichloromethane T=-78°C; 0.5 h; 2: benzaldehyde dimethyl acetal in dichloromethane T=-78°C; 0.5 h;

chloro-trimethyl-silane; tin(ll) chloride in dichloromethane T=-78°C; 1.5 h;

2,3-dicyano-5,6-dichloro-p-benzoquinone T=100°C; 2 h;

n-butyllithium in tetrahydrofuran; diethyl ether; hexane T=-78°C; 1 h;

1: 90 percent / LDA 2: tris(pentafluorophenyl)boron / CH2Cl2 / 3.5 h / 0 °C View Scheme