N-benzyl-N,N,N-triethylammonium chloride in N,N-dimethyl-formamide T=70 - 80°C; 6 h; stereochemistry investigated; also in the presence of water or BF3*OEt2; Product distribution;

sodium hydride in N,N-dimethyl-formamide T=70 - 80°C; 4.5 h; Yields of byproduct given;