Synthesis of Cyclic Alkenylsiloxanes by Semihydrogenation: A Stereospecific Route to (<i>Z</i>)-Alkenyl Polyenes
作者:Bryony L. Elbert、Diane S. W. Lim、Haraldur G. Gudmundsson、Jack A. O'Hanlon、Edward A. Anderson
DOI:10.1002/chem.201403255
日期:2014.7.7
Cyclic alkenylsiloxanes were synthesized by semihydrogenation of alkynylsilanes—a reaction previously plagued by poor stereoselectivity. The silanes, which can be synthesized on multigram scale, undergo Hiyama–Denmark coupling to give (Z)‐alkenyl polyene motifs found in bioactive natural products. The ring size of the silane is crucial: five‐membered cyclic siloxanes also couple under fluoride‐free
环状烯基硅氧烷是通过炔基硅烷的半氢化来合成的,该反应以前因立体选择性差而受到困扰。这些硅烷可以在数克规模上合成,经过 Hiyama-Denmark 偶联,得到生物活性天然产物中发现的 ( Z )-烯基多烯基序。硅烷的环大小至关重要:五元环状硅氧烷在无氟条件下也会偶联,而它们的六元同系物则不会,从而在该结构基序内实现正交性。