Synthesis and reactivity of β-phenylselanyl α-oxoesters
摘要:
beta-Phenylselanyl alpha-oxoesters 2 were prepared by N-phenylselanyl morpholine treatment of alpha-oxoesters 1, oxidized into beta-unsaturated alpha-oxoesters 5 and subjected to the Wittig-Horner olefination. The diethyl (1-phenylselanylalkyl)maleates 6 have led, after [2,3]sigmatropic rearrangement of the corresponding selenoxides, to the diethyl 3-alkylidene-2-hydroxysuccinates 7. The 2-(t-butoxycarbonylamino)-3-alkylidenesuccinates 8 were prepared in a similar way. The decomposition of halo-adducts derived from compounds 6 has allowed the synthesis of the diethyl 3-alkylidene-2-halosuccinates 9 and 10. (C) 1997 Elsevier Science Ltd.
A One-Step Synthesis of Alkyl 2-Oxo-3-alkenoates from Alkenyl Grignard Reagents and Dialkyl Oxalates
作者:M. Rambaud、M. Bakasse、G. Duguay、J. Villieras
DOI:10.1055/s-1988-27642
日期:——
The reaction of alkenyl Grignard reagents with dialkyl oxalates at 80°C in an ether/tetrahydrofuran mixture (1:1) leads to the formation of the corresponding alkyl 2-oxo-3-alkenoates in high yields. Thus a mild and convenient one-step synthesis of 3-isopropenyl-substituted 2-oxoesters is described.
β-Mercaptocarbonylverbindungen wurden mit 4-Acetoxy-2-azetidinon zu 4-Hydroxycephamderivaten kondensiert und aus diesen nach verschiedenen Methoden Δ3-Cephemderivate und das Δ3-cephem selbst hergestellt.
Simple and effective synthesis of pyrido[2,1-b]thiazines
作者:Richard W. McCabe、Douglas W. Young、Gareth M. Davies
DOI:10.1039/c39810000395
日期:——
1,3-thiazine derivatives (1, R1= h) is achieved using substituted acrylic acids under peptide coupling conditions; use of sterically hindered acrylic acids results in an anomalous reaction and the thiazine derivative (1, R1= R2= Et) gives an interesting rearrangement.
在肽偶联条件下,使用取代的丙烯酸可一步一步完成1,3-噻嗪衍生物(1,R 1 = h)的成环反应。使用位阻丙烯酸会导致反常反应,噻嗪衍生物(1,R 1 = R 2 = Et)产生有趣的重排。
Total Synthesis of Piericidin A1 and B1
作者:Martin J. Schnermann、Dale L. Boger
DOI:10.1021/ja055041f
日期:2005.11.1
The first total syntheses of piericidin A1 and B1 are disclosed and unambiguously establish the relative and absolute stereochemistry of the natural products by an approach that will facilitate the synthesis of a series of analogues. Central to the approach is an inverse electron demand Diels-Alder reaction of a N-sulfonyl-1-aza-1,3-butadiene with tetramethoxyethene followed by Lewis acid-promoted