Intramolecular annulation of aromatic rings with N-sulfonyl 1,2,3-triazoles: divergent synthesis of 3-methylene-2,3-dihydrobenzofurans and 3-methylene-2,3-dihydroindoles
作者:Xiang-Ying Tang、Yong-Sheng Zhang、Lv He、Yin Wei、Min Shi
DOI:10.1039/c4cc08343a
日期:——
The controllable synthesis of 3-methylene-2,3-dihydrobenzofurans2and 3-methylene-2,3-dihydroindoles5has been developed via cycloisomerization of N/O-tethered aryltriazoles.
A novel palladium-catalyzed regiocontrollable hydroarylation reaction of allenamides with B2pin2/H2O has been disclosed. H2O as an ideal hydrogen source was activated by B2pin2 to furnish allylamines or enamines with a broad functional group tolerance. The regioselectivity for both of the two products was up to 99 : 1 for most of the examples, which was achieved by adjusting the addition order of the
已经公开了新颖的钯催化的烯丙基酰胺与B 2 pin 2 / H 2 O的区域可控的氢芳基化反应。作为理想氢源的H 2 O被B 2 pin 2活化,以提供具有宽泛的官能团耐受性的烯丙胺或烯胺。在大多数实施例中,两种产物的区域选择性都高达99:1,这是通过调节催化剂和碘代苯衍生物的加成顺序来实现的。该机制的初步调查证明反应是一个非自由基处理和氘标记的实验表明,氢是选自H 2 O.
Ligand-Regulated Palladium-Catalyzed Regiodivergent Hydroarylation of the Distal Double Bond of Allenamides with Aryl Boronic Acid
作者:Xin Du、Huan Zhao、Xinling Li、Lizhi Zhang、Yunhui Dong、Ping Wang、Daopeng Zhang、Qing Liu、Hui Liu
DOI:10.1021/acs.joc.1c01303
日期:2021.10.1
inducing excellent E selectivity and anti-Markovnikovselectivity. (2) A switch of regioselectivity to 1,2-Markovnikov hydroarylation was obtained using bidentate phosphine ligand (dppf or Xantphos). The formed coordination Intermediate II led to the N-tether away from the Intermediate II and at the trans position of aryl, resulting in excellent E selectivity and Markovnikov selectivity. Meanwhile, tentative
在钯 (II) 催化剂存在下,实现了烯酰胺远端双键与芳基硼酸的配体调节区域发散加氢芳基化,提供了各种具有优异 E 选择性和马尔科夫尼科夫/反马尔科夫尼科夫选择性的官能化烯酰胺。提出了两种可能的配位中间体负责区域发散的氢化芳基化:(1)配位中间体 I,提议通过 MeCN、远端双键、苯基与钯的配位形成,导致芳基远离中间体 I,诱导优异的 E 选择性和抗马尔科夫尼科夫选择性。(2) 区域选择性转换为 1,2- Markovnikov使用双齿膦配体(dppf 或 Xantphos)获得氢芳基化。形成的配位中间体 II导致 N-tether 远离中间体 II并位于芳基的反式位置,从而导致优异的 E 选择性和马尔可夫尼科夫选择性。同时,对机理的初步研究证明,这种加氢芳基化的氢源更可能是硼酸。芳基硼酸和钯催化剂之间的金属转移是这种转变的第一步。
Iron‐Mediated Cyclization of 1,3‐Diynyl Propargyl Aryl Ethers with Dibutyl Diselenide: Synthesis of Selenophene‐Fused Chromenes
作者:Guilherme Lutz、Davi F. Back、Gilson Zeni
DOI:10.1002/adsc.201901410
日期:2020.3.4
of selenophene‐fused chromene derivatives starting from 1,3‐diynyl propargyl aryl ethers is reported herein. The method is based on carbon‐carbon, carbon‐selenium, selenium‐carbon and carbon‐selenium bonds formation in a one‐pot protocol, using iron(III) chloride and dibutyl diselenide as promoters. The same reaction conditions were applied to propargyl anilines leading to the formation of 1‐(buty
Dynamic Kinetic Resolution in Gold-Catalyzed (4 + 2)-Annulations between Alkynyl Benzaldehydes and Allenamides to Yield Enantioenriched All-Carbon Diarylalkylmethane Derivatives
作者:Yashwant Bhaskar Pandit、Rai-Shung Liu
DOI:10.1021/acs.orglett.1c03963
日期:2022.1.21
This work reports the synthesis of diarylmethane derivatives via gold-catalyzed (4 + 2)-annulations between alkynyl benzaldehydes and allenamides, followed by an aza-Claisen rearrangement. Deuterium labeling and crossover experiments have been performed to confirm this proposed mechanism. With racemic 3-substituted allenamides in a substrate ratio (1:1), we employ chiral gold catalysts to achieve a