3-Halopropenyl esters as precursors of a new class of oxygen-substituted allylic organometallic compounds: Applications in organic synthesis
3-Halopropenyl esters as precursors of a new class of oxygen-substituted allylic organometallic compounds: Applications in organic synthesis
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3-卤代丙烯酯作为新型氧取代烯丙基有机金属化合物的前体：在有机合成中的应用
DOI：
10.1351/pac200476030657
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
C. Trombini
中科院分区：
文献类型：
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作者：
M. Lombardo;Sebastiano Licciulli;C. Trombini
摘要 3-卤代丙烯酯很容易通过酰基卤与丙烯醛加成制备，与锌、铟和铬(II)反应，从而开辟了制备一类新型氧取代烯丙基有机金属化合物的途径。铟和锌试剂可以顺利地添加到羰基化合物中，在各种合成程序中提供alk-1-en-3,4-二醇衍生物，包括典型的格氏逐步条件以及Barbier一锅法。在水或非质子溶剂中使用锌和铟，发现简单的非对映选择性取决于羰基化合物的性质；共轭醛有利于顺式加合物的形成，而非共轭醛有利于反加合物的形成。转向铬，观察到区域选择性的逆转有利于 (Z)-4-羟基-烯醇乙酸酯，即高羟醛的灵活保护形式。基于氧化还原 Mn(0)/Cr(III) 对和 TMSCl 的组合使用，在催化循环中生成铬络合物。当 Cr 催化反应在 Jacobsen's Salen 配体存在下进行时，反应的区域化学结果再次逆转，并在高 ee 下形成 syn-alk-1-en-3,4-二醇。
Abstract 3-halopropenyl esters, readily prepared by the addition of acyl halides to acrolein, react with zinc, indium, and chromium(II), thus opening a route to a new class of oxygen-substituted allylic organometallic compounds. Indium and zinc reagents smoothly add to carbonyl compounds, affording alk-1-en-3,4-diol derivatives in a variety of synthetic procedures which include typical Grignard stepwise conditions as well as Barbier one-pot protocols. Using zinc and indium in water or aprotic solvents, simple diastereoselectivity was found to depend on the nature of the carbonyl compound; conjugated aldehydes favor formation of syn-adducts while unconjugated aldehydes favor anti-adducts. Moving to chromium, a reversal of regioselectivity was observed in favor of (Z)-4-hydroxy-enolacetates, flexible protected forms of homoaldols. Chromium complexes are generated in a catalytic cycle based on the combined use of the redox Mn(0)/Cr(III) couple and of TMSCl. When the Cr-catalyzed reaction is carried out in the presence of Jacobsen's Salen ligand, the regiochemical outcome of the reaction is again reversed, and syn-alk-1-en-3,4-diols are formed in high ee's.