Controlled Single and Double Iodofluorination of Alkynes with DIH- and HF-Based Reagents
作者:Lukas Pfeifer、Véronique Gouverneur
DOI:10.1021/acs.orglett.8b00321
日期:2018.3.16
terminal alkynes using 1,3-diiodo-5,5,-dimethylhydantoin and HF-based reagents is disclosed. This approach is used to prepare a fluorinated tamoxifen derivative in two steps from commercially available starting materials. A facile method enabling controlled regioselective double iodofluorination of terminal alkynes is also presented.
Recent Developments in the Chemistry of Heteroaromatic N-Oxides
作者:Liming Zhang、Youliang Wang
DOI:10.1055/s-0034-1379884
日期:——
ortho-Alkyl C–H Functionalization 4.3.3 N-Oxide Directed Remote C–H Functionalization 4.4 1,3-Dipolar Cycloaddition 5 Conclusion and Outlook Selected developments in the chemistry of heteroaromatic N-oxides since 2001 are presented in this review. The use of these N-oxides, both in late-transition-metal-catalyzed oxidations of carbon–carbon triple bonds and in regioselective C–H functionalizations of the heteroarene
Expanding the Scope of Arylsulfonylacetylenes as Alkynylating Reagents and Mechanistic Insights in the Formation of Csp<sup>2</sup>Csp and Csp<sup>3</sup>Csp Bonds from Organolithiums
作者:José Luis García Ruano、José Alemán、Leyre Marzo、Cuauhtémoc Alvarado、Mariola Tortosa、Sergio Díaz‐Tendero、Alberto Fraile
DOI:10.1002/chem.201200939
日期:2012.7.2
We describe the unexpected behavior of the arylsulfonylacetylenes, which suffer an “anti‐Michael” addition of organolithiums producing their alkynylation under very mild conditions. The broad scope, excellent yields, and simplicity of the experimental procedure are the main features of this methodology. A rational explanation of all these results can be achieved by theoretical calculations, which suggest
and proton sponge in toluene, terminalalkynes were found to undergo the alkylation by alkyl triflates to provide unsymmetrical internal alkynes. This is the first example that a simple alkyl chain other than benzylic and norbornyl units can be introduced onto the alkynyl carbon atom under Lewis acid catalysis. Mechanisticstudies revealed that the activation of the alkyne by the zinc Lewis acid and proton
Gold-Catalyzed Highly Regioselective Oxidation of C−C Triple Bonds without Acid Additives: Propargyl Moieties as Masked α,β-Unsaturated Carbonyls
作者:Biao Lu、Chaoqun Li、Liming Zhang
DOI:10.1021/ja1072614
日期:2010.10.13
Gold-catalyzed intermolecular oxidations of internal alkynes have been achieved with high regioselectivities using 8-alkylquinoline N-oxides as oxidants and in the absence of acid additives. Synthetically versatile α,β-unsaturated carbonyls are obtained in good to excellent yields and with excellent E-selectivities. A range of functional groups such as THP, MOMO, N(3), OTBS, and N-Boc are tolerated
使用 8-烷基喹啉 N-氧化物作为氧化剂并且在没有酸添加剂的情况下,已经以高区域选择性实现了内部炔烃的金催化分子间氧化。合成通用的 α,β-不饱和羰基化合物以良好到极好的收率和极好的 E 选择性获得。可以容忍一系列功能组,例如 THP、MOMO、N(3)、OTBS 和 N-Boc。该反应允许 α,β-不饱和羰基被掩蔽为炔丙基部分,从而为复杂结构合成中可能遇到的这些官能团的相容性问题提供了实用的解决方案。