Highly efficient biphasic ozonolysis of alkenes using a high-throughput film-shear flow reactor

作者：Kendall Alexander J; Barry Justin T; Seidenkranz Daniel T; Ryerson Ajay; Hiatt Colin; Salazar Chase A; Bryant Dillon J; Tyler David R

来源：Tetrahedron Letters, 2016, 57(12): 1342-1345.

DOI：10.1016/j.tetlet.2016.02.042

• Ozonolysis
• Flow chemistry
• Secondary ozonide
• Carbonyl oxide
• Film-shear reactor

A new method for ozonolysis of alkenes using a continuous flow film-shear reactor was developed. The reactor uses a shearing microfluidic mixing chamber to provide biphasic mixing of an organic phase and aqueous phase with ozone gas. The H2O acts as an in situ reducing agent for the carbonyl oxide intermediate, providing ketones and aldehydes directly from the reaction mixture. Flow rates of up to 1.0 mmol/min (alkene) with an ozone reaction efficiency of >70% were achieved. Aryl conjugated olefins reacted to form carbonyl species in good yields on a multi-gram scale; however, alkyl olefins reacted with ozone to predominantly form secondary ozonides. The discrepancy in product distributions between alkyl and aryl olefins likely originates from the electronic stability of the carbonyl oxide intermediate, which is longer lived for aryl derivatives due to conjugation.

• 出版日期2016-3-23