1: methylmagnesium bromide With copper(I) bromide dimethylsulfide complex in tetrahydrofuran T=0°C; 2: 2-(4-tert-butylcyclohexylidene)ethyl picolinate in tetrahydrofuran T=0°C; optical yield given as percent destereoselective reaction;

1: methylmagnesium bromide With copper(I) bromide dimethylsulfide complex; zinc dibromide in tetrahydrofuran T=0°C; 0.5 h; 2: 2-(4-tert-butylcyclohexylidene)ethyl picolinate in tetrahydrofuran T=0 - 20°C; optical yield given as percent destereoselective reaction;