The structural requirements for inhibition of proteasome function by the lactacystin-derived ?-lactone and synthetic analogs
摘要:
The synthesis of analogs of the lactacystin-derived beta-lactone (2) in which the substituents at C(5), C(7) and C(9) were systematically varied has led to a well defined structure-activity correlation for the highly selective inhibition of the mammalian 20 S proteasome. (C) 1999 Elsevier Science Ltd. All rights reserved.
Reaction of -silyl imines with silyi keteneacetals in the presence of ZnI2 and t-butyl alcohol, followed by treatment of the intermediate -silyl β-aminoesters with MeMgBr, produces -silyl-azetidin-2-ones in good yield; use of trimethylsilyl triflate as Lewis acid catalyst can be advantageous in some cases. The preparation of the -t-butyldimethylsilyl imine of ethyl glyoxylate in this context is detailed
Synthesis of Hypervalent Iodine(III) Reagents Containing a Transferable (Diarylmethylene)amino Group and Their Use in the Oxidative Amination of Silyl Ketene Acetals
The preparation of some hypervalent iodine reagents containing a transferable amino group derived from benzophenone imine derivatives is reported. The reagents can be readily prepared and stored as a bench‐stable solid, and were successfully used in the transition‐metal‐free oxidative amination of silyl ketene acetals to afford the corresponding α‐amino esters, the benzophenone imine moieties of which
Lithium Perchlorate Diethyl Ether/Methyl Triflate Catalyzed Transfer of Silicon from Oxygen to Carbon in Silyl Ketene (Thio) Acetals
作者:Akbar Heydari、Reza Alijanianzadeh
DOI:10.1246/cl.2003.226
日期:2003.3
Migration of a trimethylsilyl group from oxygen to the α-carbon (retro- [1,3]-Brookrearrangement) in silyl ketene acetals is catalyzed by LPDE/methyl triflate under mild conditions.
Role reversal: The title reaction has been developed to deliver α‐amino acids under very mild reaction conditions (see scheme; dpppen=1,5‐bis(diphenylphosphino)pentane). The catalysis provides a new CN bond‐forming approach for the synthesis of α‐amino acids by using an umpolung, electrophilic amination strategy.
5-MePh)2PF-Pcy2) catalyzed the enantioselective arylation of silyl keteneacetals with iodoarenes in the presence of TlOAc to promote transmetalation of silyl keteneacetals. The highest enantioselectivities giving α-arylesters up to 91% ee were achieved when (E)-1-methoxy-1-(trimethylsiloxy)propene (E/Z = 88/12) was used for the silyl keteneacetal. The effect on enantioselection of a chiral ligand is discussed
在TlOAc存在下,钯/(4-MeO-3,5-MePh)2 PF-Pcy 2)催化硅烷基乙烯酮缩醛与碘芳烃的对映选择性芳基化,以促进硅烷基乙烯酮缩醛的金属转移。当将(E)-1-甲氧基-1-(三甲基甲硅烷氧基)丙烯(E / Z = 88/12)用于甲硅烷基烯酮缩醛时,可获得最高91%ee的α-芳基酯的最高对映选择性。基于钯/(4-MeO-3,5-MePh)2 PF-Pcy 2)配合物的X射线结构以及DFT在机械方面的计算研究结果,讨论了对手性配体对映体选择的影响催化循环。