Stereoselective Synthesis of (E)- and (Z)-Isocyanoalkenes

Abstract

(E)- and (Z)-isocyanoalkenes were selectively synthesized via the sequential cross coupling of vinyl iodides with formamide, followed by dehydration. The optimal catalyst, generated in situ from Cu^II and trans-N,N'-dimethyl-1,2-cyclohexanediamine, rapidly coupled (E)- or (Z)-vinyl iodides with formamide, which minimized the isomerization of the resultant vinyl formamide. The method efficiently provided a range of acyclic, carbocyclic, and heterocyclic isocyanoalkenes; the versatility is illustrated with the selective, stereodivergent syntheses of the diastereomeric isocyanoalkene antibiotics, B371 and E-B371.