Diastereo- and Enantioselective Carbolithiation of Allyl <i>o</i>-Lithioaryl Ethers. New Chiral Cyclopropane Derivatives
作者:José Barluenga、Francisco J. Fañanás、Roberto Sanz、César Marcos
DOI:10.1021/ol026078x
日期:2002.6.1
[reaction: see text] Different allyl 2-lithioaryl ethers undergo a tandem carbolithiation/gamma-elimination in Et(2)O/TMEDA affording o-cyclopropyl phenol or naphthol derivatives in a diastereoselective manner. The use of (-)-sparteine as a chiral ligand instead of TMEDA allows the synthesis of cyclopropane derivatives with up 81% ee.
Synthesis of Benzofused <i>O</i>- and <i>N</i>-Heterocycles through Cascade Carbopalladation/Cross-Alkylation of Alkynes Involving the C–C Cleavage of Cyclobutanols
intramolecular carbopalladation of tethered alkynes with an alkylation step produced by the C–C cleavage of cyclobutanol derivatives. An alkenyl-Pd(II) intermediate has been isolated and characterized by X-ray diffraction studies. Interestingly, the nature of the tethering alkynyl chain influences the E/Z stereochemistry of the alkenyl fragment in the functionalized heterocycles.
我们报告了 Pd 催化的带有四取代烯烃片段的杂环的路线。我们的方法将束缚炔烃的分子内碳钯化与环丁醇衍生物的 C-C 裂解产生的烷基化步骤相结合。已分离出一种烯基-Pd(II) 中间体,并通过 X 射线衍射研究对其进行了表征。有趣的是,束缚炔基链的性质会影响官能化杂环中烯基片段的E / Z立体化学。