A Review on Olefin Metathesis Reactions as a Green Method for the Synthesis of Organic Compounds

Scheme 3

(a) Synthesis of the (±)-3and (±)-4 aldehydes: a) [Ru(=CHPh)Cl₂(PCy₃)₂], CH₂Cl₂, reflux, 3 h; b) CH(OEt)₃, AlCl₃, toluene, 0°C to rt, 1 h or DMF, POCl₃, CHCl₃, rt, 20 h. (b) Resolution of (±)-3 into enantiomers: a) CH(OMe)₃, p-TsOH, 80–90°C; b) (S)-(-)-1,2,4-butanetriol, p-TsOH, CHCl₃, 60°C; then crystallization from hexanes and 2-propanol at 4°C; c) p-TsOH, CH₂Cl₂, H₂O, 60°C. (c) Synthesis of (±)-9: a) NaBH₄, MeOH, THF, rt, 24 h for 7a; 48 h for (±)-7; b) NaN₃, CH₃COOH, 50°C, 3 h; c) 3-propargyluracil, CuSO₄ × 5H₂O, sodium ascorbate, EtOH, rt 4 days for (±)-9.

(a)

(b)

(c)