Highly efficient CuOx/OMS-2 catalyst for synthesis of phenoxathiin derivatives via intramolecular arylations of phenols with aryl halides

Synthesis of phenoxathiins using an iron-catalysed C-H thioarylation

Phenoxathiins are an important class of sulfur-containing heterocycle, found as the core component in numerous pharmaceutically active agents and materials. Despite this importance, there are relatively few methods for the synthesis of these heterocycles that avoid complex starting materials, harsh conditions or precious transition metals. We report a two-step synthesis of phenoxathiins from phenols using iron and copper-mediated reactions. The first step involves the accelerated ortho-thioarylation of phenols using N-(2-bromophenylthio)succinimide, catalysed by the Lewis acid, iron(III) triflimide and the Lewis base, bis(4-methoxyphenyl)sulfane. In the second step, the thioarylated products were converted to a series of phenoxathiins using a copper-mediated, Ullmann-type, C-O bond forming cyclisation reaction. The synthetic utility of this two-step approach for the preparation of biologically relevant phenoxathiins was demonstrated using natural product-based phenols.

Synthesis of diaryl sulfides based on copper-doped OMS-2

We describe a practical protocol for efficiently preparing diaryl sulfide compounds using Cu–OMS-2 as the catalyst. Cu–OMS-2 originates from manganese oxide octahedral molecular sieves modified with copper ions and catalyzes the C–S coupling reaction of substituted thiophenols and aryl halides. This protocol has the advantages of environmental friendliness, simple operation, high yields, good tolerance of functional groups, and the Cu–OMS-2 catalytic material can be recycled several times.