Macrocyclic Ferrocenyl-Bisimidazoline Palladacycle Dimers as Highly Active and Enantioselective Catalysts for the Aza-Claisen Rearrangement of Z-Configured N-para-Methoxyphenyl Trifluoroacetimidates

摘要

The PdII-catalyzed aza-Claisen (Overman) rearrangement[1] of allylic trichloro-[2] and N-para-methoxyphenyl trifluoroacetimidates[3] enables the transformation of achiral allyl imidates 2, readily prepared from allyl alcohols 1 in a single high-yielding step, to chiral enantioenriched allyl amides 3 (Scheme 1). Since the trihaloacetamide and the N-para-methoxyphenyl (PMP) protecting groups can be easily removed, the overall transformation leads to allyl amines 4, valuable building blocks for the synthesis of important compound classes such as unnatural amino acids.