Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
J Am Chem Soc. 2011 Nov 2;133(43):17142-5. doi: 10.1021/ja207585p. Epub 2011 Oct 11.
We have developed an enantioselective, copper(I)-catalyzed addition of terminal alkynes to racemic isochroman acetals. This method is one of the first transition-metal-catalyzed approaches to enantioselective additions to prochiral oxocarbenium ions. In this reaction, TMSOTf is used to form the oxocarbenium ion in situ under conditions compatible with simultaneous formation of the chiral copper acetylide. By using a bis(oxazoline) ligand, good yields and enantioselectivities are observed for a variety of enantioenriched 1-alkynyl isochromans.
我们开发了一种对映选择性的铜(I)催化的末端炔烃与消旋异苯并呋喃缩醛的加成反应。这种方法是首例过渡金属催化的对前手性氧杂碳翁离子的对映选择性加成反应之一。在这个反应中,TMSOTf 在与同时形成手性铜炔化物相容的条件下原位形成氧杂碳翁离子。通过使用双(恶唑啉)配体,对于各种具有丰富对映体的 1-炔基异苯并呋喃,可以观察到良好的收率和对映选择性。