In this account, recent accomplishments in the field of target-oriented synthesis involving allenes are summarized. Allenic α-amino acid derivatives 9, which are of interest as possible vitamin B 6 decarboxylase inhibitors, were prepared by 1,6-addition of the cyano-Gilman reagent t-Bu 2 CuLi-LiCN to 2-amino-substituted enynoates 8. and selective deprotection at either the amino or the ester group
Zinc-Catalyzed Multicomponent Reactions: Easy Access to Furyl-Substituted Cyclopropane and 1,2-Dioxolane Derivatives
作者:Sergio Mata、Jesús González、Rubén Vicente、Luis A. López
DOI:10.1002/ejoc.201600393
日期:2016.5
cyclopropyl-substituted furan derivatives by a zinc-catalyzed three-component coupling of 1,3-dicarbonylic compounds, 2-alkynals and alkenes is reported. A sequence consisting of an initial Knoevenagel condensation, cyclization, and a final cyclopropanation reaction would account for the formation of the final products. In most cases, this multicomponent process proceeds in good yield under mild reaction conditions and
We have isolated the sulfonylbuta-1,3-diynes 3 and 5 as colorless prisms, which demonstrate unprecedented dimerization. Furthermore, the reactions of 3 and 5 with alkoxides or buta-1,3-dienes were examined and the products obtained were either sulfonyl-β-alkoxybut-1-en-3-ynes 16a–e, β-alkoxybut-3-en-1-ynes 17a–d or the cycloadducts 23 and 24a,b.
The purpose of this study is to point out the synthetic utility of a new class of Michael acceptors (nitrodienes and nitroenynes). The highly enantioselective organocatalytic Michael addition of carbonylcompounds to these functionalized nitroolefins has been carried out in the presence of (S)‐diphenylprolinol silyl ether to achieve some interesting building blocks in high selectivities. The adducts
With an odor threshold value of 0.54 ng L–1 air, (3E,5E)-7,7-dimethyl-5-tert-butylocta-3,5-dien-2-one (1a) constitutes the most potent member of a new family of acyclic muskodorants with ionone aspects. Replacement of the quaternary carbon atoms of 1a with silicon atoms leads to the (di)sila analogues 1b (replacement of the carbon atom C-7), 1c (replacement of the quaternary carbon atom of the 5-tert-butyl
气味阈值为 0.54 ng L–1 空气,(3E,5E)-7,7-dimethyl-5-tert-butylocta-3,5-dien-2-one (1a) 构成了具有紫罗兰酮特性的新系列无环麝香气味剂。用硅原子替换 1a 的季碳原子导致 (di) sila 类似物 1b(替换碳原子 C-7)、1c(替换 5-叔丁基的季碳原子)和1d(两个季碳原子的置换)。化合物 1b-1d 是通过多步合成制备的,并表征了它们的嗅觉特性。disila 类似物 1d 被证明是该系列中最弱的化合物(197 ng L-1 空气),只有非常微弱的麝香方面。7-sila 类似物 1b 非常花香,具有紫罗兰酮和玫瑰的特征,还具有明显的麝香调(1.63 ng L-1 空气)。5-三甲基甲硅烷基类似物 1c 是该系列中最有麝香味的 sila 气味剂(10.6 ng L-1 空气),具有玫瑰色但不是紫罗兰酮样的小面。因此,将