Enzymatic thiol Michael addition using laccases: Multiple C[sbnd]S bond formation between p-hydroquinones and aromatic thiols

Abstract

Laccases create CC, CO or CN bonds and have been investigated intensively as catalysts for green chemistry and white biotechnology. However, little is known about CS bond formation in laccase-catalyzed reactions. We have used the laccases from Pycnoporus cinnabarinus and Myceliophthora thermophila to create heteromolecular reaction products from p-hydroquinones and aromatic thiols via CS bond formation. We discovered a broad assortment of different thiolated products, ranging from dimers to tetramers. During laccase-catalysis of the aromatic thiols without p-hydroquinones homomolecular dimers were formed and these were always linked by SS bonds. The use of laccase is a convenient way to form heteromolecular thiolated products and homomolecular SS bonds under eco-friendly environments.