Efficient synthesis of fumaric amides through cross-metathesis of acrylic amides with the NHC Grubbs ruthenium catalyst

Application of the second generation Grubbs metathesis catalyst for the homo-cross-metathesis of acroyl amides from chiral amines is reported. This efficient and high-yielding reaction provides a side-product free synthesis of fumaric acid diamides which are formed with complete (E)-selectivity under the reaction conditions. In particular, products which cannot be synthesized from the corresponding fumaroyl chloride via classic condensation route can now be provided in excellent yields (88–98%) with a catalyst loading from 2.5 mol% to even 0.375 mol%.