Addition of secondary amines to alkynylphosphonates

Addition of secondary amines to alkynylphosphonates catalyzed by Cu(I) salts proceeds regio- and stereospecifically to form (E)-2-(dialkylamino)alkenylphosphonates. The E-confguration was proved by analysis of C-13-P-31 vicinal spin-spin coupling constants in the NMR spectra of the products and authentic model compounds. The (3)J(PC) constants in the model compounds fall in the range of 6-12 Hz for the cis arrangement of the coupled nuclei and are equal to or higher than 16 Hz for the trans configuration. Related coupling constants in the addition products are around 5 Hz, that is, corresponding to cis coupling. (C) 2001 Elsevier Science Ltd. All rights reserved.