Enhanced Diels–Alder reactions: on the role of mineral catalysts and microwave irradiation in ionic liquids as recyclable media
摘要:
This manuscript explores in detail the combined effect of solid supports or microwave irradiation in ionic liquids on a series of Diels-Alder reactions involving 1,3-cyclopentadiene and numerous dienophiles. (c) 2007 Elsevier Ltd. All rights reserved.
Toward a mild dehydroformylation using base-metal catalysis
作者:Dylan J. Abrams、Julian G. West、Erik J. Sorensen
DOI:10.1039/c6sc04607j
日期:——
biosynthesis of cholesterol and related sterols under mild conditions using base-metal catalysts. In contrast, chemists have recently developed a non-oxidative dehydroformylation method; however, it requires high temperatures and a precious-metal catalyst. Careful study of both approaches has informed our efforts to design a base-metal catalyzed, mild dehydroformylation method that incorporates benefits from
Dilithium 2,2′-methylenebis(4,6-di-tert-butylphenoxide) as a bidentate Lewis acid in organic synthesis
作者:Takashi Ooi、Akira Saito、Keiji Maruoka
DOI:10.1016/s0040-4039(98)00575-9
日期:1998.5
Dilithium 2,2'-methylenebis(4,6-di-tert-butylphenoxide) can be successfully utilized as a bidentate Lewis acid for simultaneous coordination to carbonyl groups, thereby accelerating the Diels-Alder reactions. The double activation ability of the bidentate lithium reagent toward carbonyls is emphasized in comparison with the corresponding monodentate lithium reagent. (C) 1998 Elsevier Science Ltd. All rights reserved.
Enantioselective Synthesis of Cyclothiazide Analogues: Novel Probes of the Stereospecific Actions of Benzothiadiazines at AMPA-Type Glutamate Receptors
作者:Yuefei Hu、Kelvin A. Yamada、David K. Chalmers、Durga P. Annavajjula、Douglas F. Covey
DOI:10.1021/ja9525317
日期:1996.1.1
The stereospecific interactions of the eight stereoisomers of dihydromethylcyclothiazide, an analogue of cyclothiazide, with AMPA-type glutamate receptors was investigated using electrophysiological methods that measured the ability of each stereoisomer to inhibit AMPA receptor desensitization. The eight stereoisomers were obtained by HPLC separation of four pairs of enantiomerically pure (>95% ee) diastereomers prepared from (1R-exo)-, (1R-endo)-, (1S-exo)-, and (1S-endo)-2-methylbicyclo[2.2.1]heptane-2-carboxaldehyde intermediates. The desensitization process was blocked most potently by [1S-[1 alpha,2 alpha(R*),4 alpha]]-dihydromethylcyclothiazide, one of the stereoisomers prepared from the (1S-endo)-carboxaldehyde. The smallest effects on the desensitization process were found for the four stereoisomers prepared from the (1R-exo)- and (1R-endo)-carboxaldehydes. Significant differences in the ability to inhibit desensitization were observed between all diastereomer pairs except those prepared from the (1S-exo)-carboxaldehyde.