Dissecting Alkynes: Full Cleavage of Polarized C C Moiety via Sequential Bis-Michael Addition/Retro-Mannich Cascade

作者:Roy Saumya; Davydova Maria P; Pal Runa; Gilmore Kerry; Tolstikov Genrikh A; Vasilevsky Sergei F*; Alabugin Igor V
来源:Journal of Organic Chemistry, 2011, 76(18): 7482-7490.
DOI:10.1021/jo201259j

摘要

The reaction of diaryl ketoalkynes with 1,2-diamino ethane leads to e full scission of the triple bond with the formation of acetophenone and imidazoline fragments. In this transformation, one of the alkyne carbons undergoes formal reduction with the formation of three C-H bonds, whereas the other carbon undergoes formal oxidation via the formation of three C-N bonds (one pi and two sigma). Computational analysis confirmed that the key fragmentation step proceeds via a six-membered TS in a concerted manner. Both amines are involved in the fragmentation: the N-H moiety of one amine transfers a proton to the developing negative charge at the enolate oxygen, while the other amine provides direct stereoelectronic assistance to the C-C bond cleavage via a hyperconjugative n(N)->sigma*(C-C) interaction.

  • 出版日期2011-9-16