Reactions of acetylenes derived from glyceraldehyde and propargyl aldehyde show remarkable reactivity in Kinugasa cycloaddition/rearrangement cascade process catalyzed by Cu(I) ion. Reactions proceed by formation of a rigid dinuclear copper(I) complex in which each copper ion is coordinated to one or both oxygen atoms in the acetylene molecule and to both triple bonds. It has been demonstrated that
The synthesis of unnatural α-alkyl- and α-aryl-substituted serine derivatives
作者:Aleksandra Narczyk、Sebastian Stecko
DOI:10.1039/c9ob02472g
日期:——
The synthesis of α-aryl- and α-alkyl-substituted serine derivatives via [3,3]-sigmatropic rearrangement of allyl carbamates as a key step is reported. Allyl carbamates were obtained from the corresponding allyl alcohols. The former were prepared through three approaches. Aryl-substituted ones were synthesized via the Stille coupling reaction of aryl iodides with enantiomerically enriched vinyl stannanes
The Synthesis of 5-Amino-dihydrobenzo[<i>b</i>]oxepines and 5-Amino-dihydrobenzo[<i>b</i>]azepines via Ichikawa Rearrangement and Ring-Closing Metathesis
The combination of Ichikawa’s rearrangement and a ring-closing metathesis reaction of allyl carbamates is presented as a method for the preparation of 5-amino-substituted 2,5-dihydro-benzo[b]oxepines, 2,5-dihydro-benzo[b]azepines, and 2,5-dihydro-benzo[b]thiepins. It was demonstrated that the use of nonracemic allyl carbamates enables the synthesis of enantioenriched benzo-fused seven-membered heterocycles
市川的重排和烯丙基氨基甲酸酯的闭环复分解反应的组合是作为用于制备5-氨基-取代的2,5-二氢-苯并[方法b ] oxepines,2,5-二氢-苯并[ b ] zepines和2,5-二氢-苯并[ b ]噻吩类。已经证明,使用非外消旋的烯丙基氨基甲酸酯能够合成对映体富集的苯并稠合的七元杂环。最后,显示了所获得结构的进一步功能化允许获得具有药理活性的5-氨基取代的2,3,4,5-四氢-1-苯并[ b ]奥沙平支架。
An Entry to the Carbapenem Antibiotic Scaffold via the Asymmetric Kinugasa Reaction
entry toward thienamycin and related compounds. The copper(I)-mediated reaction between five-membered cyclic nitrones and terminal acetylenes, leading to the assembly of the basic skeleton of carbapenemantibiotics is described. The diastereoselectivity of this cycloaddition–rearrangement cascade, a process known as the Kinugasa reaction, with respect to the structure and configuration of both substrates
shifts of the H-2 proton and geminal protons of the protected alkoxymethyl group at the C-2 carbon atom. The differences of 1 H NMR chemical shifts of these protons fall in two ranges of about 3.3-3.7 ppm, and 4.0-4.4 ppm. This observation can be attributed to the influence of the anisotropy of the neighboring carbonylgroup and can be easily correlated with configuration at the bridgehead carbon atom