From Planning to Optimization: Total Synthesis of Valerenic Acid and Some Bioactive Derivatives
作者:Juergen Ramharter、Johann Mulzer
DOI:10.1002/ejoc.201101834
日期:2012.4
The streamlined synthesis implements a new one-pot reaction, which combines the addition of a Grignard species with an acid-catalyzed isomerization of the intermediate allylic alcohol. Further highlights are a stereo- and regioselective hydroxy-directed Diels–Alder reaction, a hydroxy-directed hydrogenation, and a final Negishi coupling reaction. After optimization of our synthesis, the preparation
acceleration effect of an allylic hydroxy group on ring-closing enyne metathesis has been found. Ring-closing enyne metathesis of terminalalkynes possessing an allylic hydroxy group proceeded smoothly without the ethylene atmosphere generally necessary to promote the reaction. The synthesis of (+)-isofagomine with the aid of this efficient reaction has been demonstrated. Mechanistic studies of the acceleration
[4+2+2] Cycloaddition catalyzed by a new cationic rhodium–bisphosphine monooxide complex
作者:Gino Martin R. Canlas、Scott R. Gilbertson
DOI:10.1039/c4cc01320d
日期:——
A rhodium–BozPHOS based complex is reported that is competent in catalyzing the [4+2+2] cycloisomerization of cyclooctatrienes in moderate to good yields.
Novel approach to seven-membered rings by the intramolecular tandem cyclopropanation/cope rearrangement sequence
作者:Huw M.L. Davies、C.E.Michael Oldenburg、Melinda J. McAfee、J.Greg Nordahl、John P. Henretta、Karen R. Romines
DOI:10.1016/0040-4039(88)85312-7
日期:1988.1
The intramolecular tandem cyclopropanation/Cope rearrangement sequence between rhodium(II) acetate stabilized vinylcarbenoids and dienes is a feasible method for the stereospecific synthesis of fused seven-memberedrings.
Acceleration effect of allylic hydroxy group on ring-closing enyne metathesis of terminal alkynes: scope and application to the synthesis of isofagomine
substituent effect on ring-closing enyne metathesis has been found. An allylic hydroxy group on enyne substrates accelerates ring-closing enyne metathesis of terminalalkynes. The reaction proceeds smoothly without ethylene atmosphere and/or more reactive newer generation Ru-carbene catalysts, which are generally necessary to promote the reaction. This efficient reaction was applied to the synthesis of