Substitution Reactions of Propargylic Acetates with Organoaluminum Reagents

• Main Authors: Hua-Chuan Shih, 施樺娟
• Other Authors: Han-Mou Gau
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/16587120955569729530

碩士 === 國立中興大學 === 化學系所 === 100 === This thesis reports an effective, convenient, and mild substitution reaction system of propargylic acetates with aluminum reagents. Effects of temperatures, coordinating or non-coordinating solvents, concentrations of substrates, and reaction times were studied. In this study, substituted propargyl acetates were prepared easily from reactions of a wide variety of aldehydes and several lithium acetylides under reaction conditions of -78 oC for 2 h in the presence of excess amounts of acetyl anhydride. The aldehydes include aromatic aldehydes, 2-thienyl aldehyde, aliphatic aldehydes, and α,β-unsaturated alkenyl aldehydes or alkynyl aldehydes. Yields of propargylic acetates range from 59-90 %. Substitution reactions of proparylic acetates with 1.4 equiv. of AlR3 (R = Me, Et, Ph) proceed effectively in toluene at room temperature in a short reaction time of in general 1 min to afford substituted alkynes in good to excellent yields of up to 92 %. However, the substitution reaction of the propargylic acetate derived from n-hexanal requires 60 ˚C, 3 hours to give the product in a yield of 68%. Interestingly, the substitution reactions of alkenyl proparylic acetates with AlMe3 produce a mixture two isomeric en-yne products.