Bioorthogonal Hydroamination of Push–Pull‐Activated Linear Alkynes
作者:Dahye Kang、Sheldon T. Cheung、Justin Kim
DOI:10.1002/anie.202104863
日期:2021.7.26
adequately protecting it against cellular nucleophiles. This design preserves the low steric profile of an alkyne and pairs it with a comparably unobtrusive hydroxylamine. The kinetics are on par with those of the fastest strain-promoted azide-alkyne cycloaddition reactions, the products regioselectively formed, the components sufficiently stable and easily installed, and the reaction suitable for cellular
N , N之间的生物正交反应描述了-二烷基羟胺和推拉活化卤代炔烃。我们探索了再杂化效应在激活炔烃中的应用,并且我们表明,当竞争的立体电子和感应因子得到适当平衡时,电子效应在未催化的共轭逆 Cope 消除反应中充分激活线性炔烃,同时充分保护其免受细胞亲核试剂的侵害。这种设计保留了炔烃的低空间分布,并将其与相对不显眼的羟胺配对。动力学与最快的应变促进叠氮化物-炔烃环加成反应相当,产物区域选择性形成,组分足够稳定且易于安装,反应适合细胞标记。
Asymmetric Synthesis of Ramariolides A and C through Bimetallic Cascade Cyclization and <i>Z</i>–<i>E</i> Isomerization Reaction
作者:Pratik Pal、Samik Nanda
DOI:10.1021/acs.orglett.7b00202
日期:2017.3.3
A short and flexible asymmetric synthesis of ramariolides A and C was accomplished. A bimetallic catalytic system consisting of Pd–Cu-mediated cascade cyclization, unprecedented Z–E isomerization by a Ru-based metathesis catalyst, and late-stage stereoselective epoxidation are the key steps involved in the synthesis.
New mono‐ and bicyclic nitrones containing a CF2 group have been efficiently synthetized starting from propargylic fluorides. The key steps involve isomerization of propargylic alcohols to enones, followed by nucleophilic addition of nitro alkane anions and then intramolecular Michael additions. The last step is a reductive cyclisation from the nitro group.
Synthetic studies towards naturally occurring γ-(<i>Z</i>)/(<i>E</i>)-alkylidenebutenolides through bimetallic cascade cyclization and an adventitious photoisomerization method
visible light-induced photoisomerization method of γ-(Z)-alkylidenebutenolides to their corresponding E-components was reported in this article. Initially, a series of naturally occurring enantiopure γ-(Z)-alkylidenebutenolides was synthesized by employing a “Pd–Cu” bimetallic cascade cyclization protocol. In the later part, the synthesized γ-(Z)-alkylidenebutenolides were photoisomerized in the presence
本文报道了一种通用且灵活的可见光诱导γ-( Z )-亚烷基丁烯内酯光致异构化为其相应的E-组分的方法。最初,通过采用“Pd-Cu”双金属级联环化方案合成了一系列天然存在的对映体纯 γ-( Z )-亚烷基丁烯内酯。在后面的部分中,合成的 γ-( Z )-亚烷基丁烯内酯在三重光敏剂存在下以合理可接受的产率对 γ-( E )-亚烷基丁烯内酯进行光异构化。采用所开发的方法实现了 goniobutenolides、hygrophorones、ramariolide D、melodorinols/乙酰-melodorinols、versicolactones 和 phomopsolidones 的全合成。
In order to synthesize the major C(3)-C(12) part of fostriecin, asymmetric dihydroxylation of several dienes 5a-f, prepared by cross-coupling reactions of several types. vas studied, thus providing high dependency on the hydroxyl groups at C(5) and C(l 1). The best regioselectivity was obtained with 5d to produce diol 23. which was later transformed into the advanced intermediate 26. (C) 2002 Elsevier Science Ltd. All rights reserved.