Tandem Sonogashira-Hagihara Coupling/Cycloisomerization Reactions of Ethynylboronic Acid MIDA Ester to Afford 2-Heterocyclic Boronic Acid MIDA Esters: A Concise Route to Benzofurans, Indoles, Furopyridines and Pyrrolopyridines
摘要:
A one-pot process that provides direct access to 2-heterocyclic MIDA (N-methyliminodiacetic acid) boronates has been developed. The reaction of 2-iodophenols or 2-iodoanilines with ethynylboronic acid MIDA ester readily afforded 2-substituted heterocyclic compounds. Amidine and phosphazene bases, especially TMG (1,1,3,3-tetramethylguanidine) assumed an important role in the tandem Sonogashira-Hagihara coupling/cycloisomerization reactions.
asymmetric cycloisomerization of 1,7-enynes is regarded as a formidable challenge due to the poor ability of 1,7-enynes to serve as bidentate ligands to metal. In this Letter, a highly enantioselective rhodium(I)-catalyzed Alder-ene-type cycloisomerization of 1,7-enynes is disclosed, offering an efficient method for the synthesis of a wide range of fused six-membered cyclic compounds. Furthermore, a high
Palladium‐Catalyzed Regioselective Synthesis of 1‐Hydroxycarbazoles Under Aerobic Conditions
作者:So Won Youn、Young Ho Kim、Yoon Hyung Jo
DOI:10.1002/adsc.201801265
日期:2019.2
A palladium‐catalyzed aerobic C−H amidation of N‐Ts‐2‐amino‐3′‐hydroxylbiaryls has been developed to afford a diverse range of 1‐hydroxycarbazoles with high regioselectivity and efficiency. This protocol benefits from operational simplicity, robustness, and sustainability with the use of ambient air as the sole terminal oxidant. Further elaboration of the products obtained from this process provides
An Approach to Cyclohepta[<i>b</i>]indoles through an Allenamide (4 + 3) Cycloaddition–Grignard Cyclization–Chugaev Elimination Sequence
作者:Shuzhong He、Richard P. Hsung、William R. Presser、Zhi-Xiong Ma、Bryan J. Haugen
DOI:10.1021/ol5006455
日期:2014.4.18
A strategy for synthesizing highly functionalized cyclohepta[b]indoles through a concise (4 + 3) cycloaddition–cyclization–elimination sequence is described. The cycloaddition features nitrogen-stabilized oxyallylcations derived from epoxidations of N-aryl-N-sulfonyl-substituted allenamides, while the cyclization and elimination employed an intramolecular Grignard addition and a one-step Chugaev process
Asymmetric Counteranion Directed Catalytic Heck/Tsuji–Trost Annulation of Aryl Iodides and 1,3-Dienes
作者:Jia-Cheng Xu、Yi-Zhuo Yin、Zhi-Yong Han
DOI:10.1021/acs.orglett.1c00910
日期:2021.5.21
anion-mediated asymmetric Heck/Tsuji–Trost reaction of aryliodides and 1,3-dienes is presented. Chiral indoline derivatives could be afforded with remarkably higher yields and enantioselectivities than our previous chiral ligand-based method. Silver carbonate is employed as both base and halide scavenger to ensure fast and recyclable exchange of the catalytic amount of chiral anions. Fast salt metathesis,
Parallel strategies for the synthesis of annulated pyrido[3,4-b]indoles via Rh(I)- and Pd(0)-catalyzed cyclotrimerization
作者:Bianca M. Saliba、Satyam Khanal、Michael A. O'Donnell、Kathryn E. Queenan、Junho Song、Matthew R. Gentile、Seann P. Mulcahy
DOI:10.1016/j.tetlet.2018.10.050
日期:2018.12
Two different pathways for the synthesis of annulated pyrido[3,4-b]indoles are reported using metal-catalyzed cyclotrimerization reactions. A stepwise process using Rh(I)-catalysis in the final step of the synthesis and a multicomponent, tandem catalytic approach using Pd(0)-catalysis both lead to complex nitrogen-containing heterocycles in good yields. Substituent effects are investigated for both
使用金属催化的环三聚反应已报道了两种合成环式吡啶并[3,4- b ]吲哚的不同途径。在合成的最后一步中使用Rh(I)催化的分步过程和使用Pd(0)催化的多组分串联催化方法均会以高收率产生复杂的含氮杂环。研究了两种途径的取代基效应,表明Pd(0)催化的方法对吸电子基团更敏感。