Biotransformations, Chemoenzymatic, Chirality, Siloxane, Transesterification
An approach employing two enzymes—toluene dioxygenase and immobilized lipase B from Candida antarctica (N435)—was explored as a potential biocatalytic method for the coupling of chiral diols with siloxane species. Analysis of reaction mixtures using1H NMR spectroscopy suggested that up to 66% consumption of the siloxane starting materials had occurred. Oligomeric species were observed and chiral products from the coupling of a cyclic diol with a siloxane molecule were isolated and characterized by MALDI-ToF MS and GPC. Immobilized lipases from Rhizomucor miehei and Thermomyces lanuginosus were also explored as potential catalysts for the coupling reactions, however, their use only returned starting material.
Naoum, Ravi; Séguin, Jacqueline P.; Trant, John F.; Frampton, Mark B.; Hudlický, Tomáš; and Zelisko, Paul M.. (2016). A chemoenzymatic route to chiral siloxanes. Tetrahedron, 72 (27-28), 4027-4031.