Stereoselective Rh<sub>2</sub>(<i>S</i>-IBAZ)<sub>4</sub>-Catalyzed Cyclopropanation of Alkenes, Alkynes, and Allenes: Asymmetric Synthesis of Diacceptor Cyclopropylphosphonates and Alkylidenecyclopropanes
作者:Vincent N. G. Lindsay、Dominic Fiset、Philipp J. Gritsch、Soula Azzi、André B. Charette
DOI:10.1021/ja3099728
日期:2013.1.30
A mild and highly stereoselective rhodium(II)-catalyzed cyclopropanation of alkenes, alkynes, and allenes with diacceptor diazo compounds is reported. Using the phosphonate moiety as an efficient trans-directing group, the first catalytic asymmetric route to diacceptor cycloprop(en)ylphosphonates was developed by employing an α-cyano diazophosphonate and Rh(2)(S-IBAZ)(4) as chiral catalyst. The isosteric
报道了一种温和且高度立体选择性的铑 (II) 催化的烯烃、炔烃和丙二烯与二受体重氮化合物的环丙烷化反应。使用膦酸酯部分作为有效的反式导向基团,通过使用 α-氰基重氮膦酸酯和 Rh(2)(S-IBAZ)(4) 作为手性催化剂,开发了第一个催化不对称二受体环丙(烯)基膦酸酯的路线。膦酸和羧酸衍生物的等排特性允许在该过程中替代使用 α-氰基重氮酯,从而以高产率和立体选择性生成 α-氰基环丙(烯)基羧酸酯。利用该系统中涉及的氰基卡宾中间体的特殊反应性,相容底物的范围可以扩展到取代的丙二烯,
Ligand Controlled Highly Selective Copper-Catalyzed Borylcuprations of Allenes with Bis(pinacolato)diboron
作者:Weiming Yuan、Shengming Ma
DOI:10.1002/adsc.201100929
日期:2012.7.9
Copper‐catalyzed highlyselectiveborylcuprations of allenes with bis(pinacolato)diboron produce two different types of alkenylboranes by applying a ligand effect. In the presence of tris(para‐methoxyphenyl)phosphine [P(C6H4OMe‐p)3], the reaction of aryl‐1,2‐dienes affords 2‐alken‐2‐yl boronates as the only product with exclusive Z‐geometry; the regioselectivity is switched to afford the 1‐alken‐2‐yl
铜催化的具有双(频哪醇)二硼烷的丙二烯的高选择性硼烷基cup通过施加配体效应产生两种不同类型的烯基硼烷。在存在三(对-甲氧基苯基)膦[P(C 6 H 4 OMe- p)3 ]的情况下,芳基1,2-二烯的反应提供2-烯丙基-2-基硼酸酯作为唯一的独家产品Z几何 当使用二齿膦2,2'-双(二苯基膦基)联苯作为配体时,区域选择性切换为主要产物1-烯丙基-2-基硼酸酯。
Modular Synthesis of Stereodefined Benzocyclobutene Derivatives via Sequential Cu- and Pd-Catalysis
作者:Fabien J. T. Talbot、Shibo Zhang、Bishnupada Satpathi、Gareth P. Howell、Gregory J. P. Perry、Giacomo E. M. Crisenza、David J. Procter
DOI:10.1021/acscatal.1c04496
日期:2021.12.3
materials and medicinal chemistry, although general routes for their provision remain underexplored. A modular, divergent, and stereoselective Cu- and Pd-catalyzed assembly/cyclization sequence allows the synthesis of densely functionalized BCBs, from readily accessible imine, allene, and diboron precursors. Preliminary results have identified enantioselective conditions for our protocol and highlighted,
苯并环丁烯 (BCB) 对材料和药物化学的兴趣越来越大,尽管其提供的一般途径仍未得到充分探索。模块化、发散和立体选择性的 Cu 和 Pd 催化的组装/环化序列允许从容易获得的亚胺、丙二烯和二硼前体合成密集功能化的 BCB。初步结果已经确定了我们协议的对映选择性条件,并强调了,例如,它适用于合成含 BCB 的肽。通过实验条件的简单变化或底物修饰,我们的策略扩展到提供二氢吲哚和喹啉衍生物,适合进一步操作。
Organomagnesium-Catalyzed Isomerization of Terminal Alkynes to Allenes and Internal Alkynes
作者:Raphaël Rochat、Koji Yamamoto、Michael J. Lopez、Haruki Nagae、Hayato Tsurugi、Kazushi Mashima
DOI:10.1002/chem.201500179
日期:2015.5.26
the transformation of these terminalalkynes into allenes and further to internalalkynes under mild conditions. To the best of our knowledge, this example is the first of an organomagnesium‐catalyzed isomerization of alkynes. Notably, the reactions proceeded through temporally separated autotandem catalysis, thus allowing the isolation of the allene or internalalkyne species in good yields. Mechanistic
Palladium‐Catalyzed Insertion of an Allene into an Aminal: Aminomethylamination of Allenes by CN Bond Activation
作者:Jianhua Hu、Yinjun Xie、Hanmin Huang
DOI:10.1002/anie.201403774
日期:2014.7.7
aminomethylamination of allenes with aminals by CN bond activation is described. This direct and operationally simple method provides a fundamentally novel approach for the synthesis of 1,3‐diamines. Mechanistic studies suggest that a unique cationic π‐allylpalladium complex containing an aminomethyl moiety is generated as a key intermediate through the carbopalladation of the allene with a cyclometalated