Diastereoselective Cobalt-Mediated [2 + 2 + 2] Cycloadditions of Substituted Linear Enediynes Phosphine Oxides: Scope and Limitations
作者:Franck Slowinski、Corinne Aubert、Max Malacria
DOI:10.1021/jo026212r
日期:2003.1.1
Variously substitutedlinearenediynes phosphines oxides possessing the double bond at either the terminal or internal position and with the phosphine oxide appended onto the alkyne or the alkene terminus have been prepared. Their cobalt(I)-mediated cyclizations produce the eta(4)-complexed tricyclic compounds in high yields. The endo/exo selectivity depends on both the position of the phosphine oxide
preparation of substitutedlinearenediyneesters bearing the double bond either at the terminal or at internal position and the ester substituent either at the alkyne or at the alkene terminus is presented. Their cobalt(I)-mediated [2+2+2] cyclizations produce the η4-complexed tricyclic compounds in very good yields. The endo/exo selectivity depends on the position of the ester in the enediyne, but the
also hinders self-assembly. Finally, substituting one methyl group of TMSA by a hydrogen atom induces self-assembly but in a different geometry, with the molecules lying flat on the goldsurface in a quasi-epitaxy mode. Our molecular approach demonstrates the key role played by the TMSA head in self-assembly, its origin being twofold: 1) the TMSA layers are commensurate to the Au(111) adlattice along
Intramolecular cobalt-mediated [2 + 2 + 2] cycloaddition of linear enediynes. A useful synthetic entry into cobalt-protected tricyclic dienes and their synthetic elaboration
作者:Ethan D. Sternberg、K. Peter C. Vollhardt
DOI:10.1021/jo00183a017
日期:1984.5
Synthesis of CpCo-complexed α-pyrans via an intramolecular [2+2+2] cycloaddition