A new highly chemoselective isomerization of allylamides
摘要:
This work describes the first iridium-catalyzed isomerization of N-allylamides into enamides. This strategy allows the chemoselective preparation of (E)-N-(1-propenyl)-enamides and can be applied for the selective deprotection of N-allylamides. (C) 2004 Elsevier Ltd. All rights reserved.
isoxazolidines were synthesized in good to excellent yields by 1,3-dipolar cycloaddition of N-vinylamide dipolarophiles and nitrones. Strikingly, solvent-free conditions gave high conversion and yields, shortened reaction time, and minimized degradation products. N-Vinyloxazolidin-2-one and its analogues used in these cycloaddition reactions were conveniently prepared in excellent yields by a modified
Re(I)-catalyzed hydropropargylation of enamides: a useful method for the preparation of 4-pentynylamine derivatives
作者:Shoya Watanabe、Akane Ario、Nobuharu Iwasawa
DOI:10.1038/s41429-019-0162-3
日期:2019.6
complex intermediate, followed by intramolecular hydrogen transfer to the iminium carbon. This method is useful for the synthesis of 4-pentynylamine derivatives from enamides and easily available propargyl ether. Moreover, tandem cyclization reaction was achieved to afford a pyrrolidine derivative in a single operation by using a secondary enamide.
Trimethylsilyl Trifluoromethanesulfonate
Mediated Addition-Cyclization of <i>N</i>-Vinyloxazolidin-2-ones
to Nitrones: An Efficient Access to 4-Substituted 5-Azaisoxazolidines
Trimethylsilyl trifluoromethanesulfonate (TMSOTf) was conveniently used to promote the reaction involving N-alkenyloxazolidin-2-ones and activated nitrones, leading to new 4-substituted 5-azaisoxazolidines in good to excellent yields. This TMSOTf-promoted procedure expanded the scope of reaction of N-vinyloxazolidin-2-ones and nitrones in complementary way to the corresponding classical 1,3-dipolar cycloaddition. Some of these adducts could not be obtained under thermal activation.
Copper-Catalyzed Coupling of Amides and Carbamates with Vinyl Halides
作者:Lei Jiang、Gabriel E. Job、Artis Klapars、Stephen L. Buchwald
DOI:10.1021/ol035355c
日期:2003.10.1
A general and efficient copper-catalyzed method for the amidation of vinyl bromides and iodides has been developed. This protocol uses a combination of 5 mol % copper iodide and 20 mol % N,N'-dimethyl ethylenediamine. Substrates bearing ester, silyl ether, and amino groups were successfully coupled under the reaction conditions. The double bond geometry of the vinyl halides was retained under the reaction conditions.