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Highly Selective Nucleophilic 4‐Aryl‐2,3‐allenylation of Malonates†
Chinese Journal of Chemistry ( IF 5.4 ) Pub Date : 2020-06-18 , DOI: 10.1002/cjoc.202000300
Shihua Song 1 , Shengming Ma 1
Affiliation  

Allenes are a class of very important compounds and the development of straightforward, efficient, and highly enantioselective synthetic strategies for allenes have attracted extensive interests. Along this line, it is well known that aryl‐substituted allenes may be readily racemized, thus, difficult to prepare in high ee. Herein, an efficient palladium‐catalyzed nucleophilic allenylation of malonates with racemic 4‐aryl‐2,3‐butadienyl carbonates has been developed. The selectivity issue of mono‐ vs. bis‐allenylation with 2‐non‐substituted malonates has been addressed. By utilizing (R)‐(–)‐DTBM‐SEGPHOS (5,5'‐bis[di(3,5‐di‐t‐butyl‐4‐methoxyphenyl)phosphino]‐4,4'‐bi‐1,3‐benzodioxole) as a chiral ligand, various aryl‐substituted allenes and bisallenes have been prepared with good to excellent yields with high chemoselectivity and enantioselectivity under mild reaction conditions. Au‐catalyzed cycloisomerization and APK (allenic Pauson–Khand) reactions affording optically active mono‐ and bicyclic products have been demonstrated.

中文翻译:

丙二酸的高度选择性亲核性4-芳基-2,3-烯丙基化†

丙二烯是一类非常重要的化合物,对丙二烯的简单,有效和高度对映选择性的合成策略的发展引起了广泛的兴趣。沿着这条线,众所周知,芳基取代的烯可以很容易地消旋,因此很难在高ee值下制备。在此,开发了一种高效的钯催化丙二酸酯与外消旋的4-芳基-2,3-丁二烯基碳酸酯的亲核烯丙基化反应。mono vs的选择性问题。已经解决了2非取代丙二酸酯的双烯丙基化作用。通过利用([R )- ( - ) - DTBM-SEGPHOS(5,5'-双[二(3,5-二-[-丁基-4-甲氧基苯基)膦] -4,4'-bi-1,3-苯并二恶唑)作为手性配体,已制备了各种芳基取代的烯和双烯烯,收率良好至优异,在温和的条件下具有高化学选择性和对映选择性反应条件。已经证明了Au催化的环异构化和APK(烯丙基Pauson–Khand)反应可提供光学活性的单环和双环产物。
更新日期:2020-06-18
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