Chiral (E,E)-1,4-dialkoxy-1,3-butadienes. 2. Conformational studies and Diels-Alder reactions with symmetric dienophiles
摘要:
The first examples of Diels-Alder reactions of chiral, C-2-symmetric (E,E)-1,4-dialkoxy-1,3-butadienes are described. The cycloadditions with maleic anhydride lead in all instances to the exclusive formation of the endo adducts. C-2h-Symmetric dienophiles such as fumaronitrile and diethyl fumarate react with variable diastereoselectivities; best results are obtained with the camphor-derived diene Id, whose reaction with diethyl fumarate takes place with complete facial selectivity. A theoretical analysis, using the SCF-MO procedure AM1, of the conformations of the dialkoxydienes has been used to rationalize the steric course of the cycloadditions. (C) 1999 Elsevier Science Ltd. All rights reserved.
A convenient synthesis of hexacarbonyldicobalt complexes of chiral (non-racemic) terminal alkoxyacetylenes
摘要:
The hexacarbonyldicobalt complexes of chiral (non-racemic) unsubstituted terminal alkoxyacetylenes have been synthesized for the first time by a novel procedure that involves one-pot transformation of a chiral alcohol to the corresponding trimethylsilylated alkoxy acetylene, followed by complexation and protodesilylation (also one-pot). The synthesis is efficient and amenable to the preparation of multigram quantities.
Experimental and theoretical studies on the diastereoselective diels-alder reactions of chiral 1-alkoxy-1,3-butadienes. I: Parent system and 4-substituted derivatives
作者:Marina Virgili、Miquel A Pericàs、Albert Moyano、Antoni Riera
DOI:10.1016/s0040-4020(97)00854-5
日期:1997.9
Chiral 1-alkoxy-1,3-dienes (parent and 4-substituted) have been prepared from the corresponding chiral alkoxyacetylenes in a stereoselective manner following a 2C + 2C approach. The Diels-Alder reactions of the dienes with maleic anhydride and 4-phenyl-3H-1,2,4-triazoline-3,5-dione take place with significant diastereoselectivity. Theoretical calculations on these cycloadditions, performed with the
按照2C + 2C方法,从相应的手性烷氧基乙炔以立体选择性的方式制备了手性1-烷氧基-1,3-二烯(母体和4-取代的)。二烯与马来酸酐和4-苯基-3 H -1,2,4-三唑啉-3,5-二酮的狄尔斯-阿尔德反应具有非对映选择性。用SCF-MO方法AM1进行的这些环加成反应的理论计算已用于加合物的立体化学分配中。
作者:Marina Virgili、Albert Moyano、Miquel A. Pericàs、Antoni Riera
DOI:10.1016/s0040-4039(97)01622-5
日期:1997.9
A two step, totally stereoselectivesynthesis of (E,E)-1,4-dialkoxy-1,3-butadienes from chiral secondary alcohols has been developed. The key step involves the regio- and stereoselective hydrozirconation of alkoxyethynes derived from chiral alcohols; the intermediate (E)-(2-alkoxyvinyl)zirconium compounds, after treatment with cuprous chloride and thermally induced decomposition of the corresponding
Chiral auxiliary-induced stereocontrol in intramolecular Pauson-Khand reactions leading to angular triquinanes
作者:Jordi Tormo、Xavier Verdaguer、Albert Moyano、Miquel A Pericàs、Antoni Riera
DOI:10.1016/0040-4020(96)00844-7
日期:1996.10
thermally induced Pauson-Khandintramolecular cyclization of 1-(3-alkoxy-2-propynyloxy)methylcyclopentenes (2) and 1-(5-alkoxy-4-pentynyl)cyclopentenes (3), derivedfromchiral secondary alcohols, leads to the tricyclic enones (9) and (10), respectively, in moderate yields and with variable diastereoselectivities. Among the chiral alcohols that we have examined, enynes derivedfrom Oppolzer's 3-(ne
Enantioselective Construction of Angular Triquinanes through an Asymmetric Intramolecular Pauson−Khand Reaction. Synthesis of (+)-15-Nor-pentalenene
作者:Jordi Tormo、Albert Moyano、Miquel A. Pericàs、Antoni Riera
DOI:10.1021/jo9700538
日期:1997.7.1
Chiral (E,E)-1,4-dialkoxy-1,3-butadienes. 2. Conformational studies and Diels-Alder reactions with symmetric dienophiles
作者:Marina Virgili、Albert Moyano、Miquel A. Pericàs、Antoni Riera
DOI:10.1016/s0040-4020(99)00086-1
日期:1999.3
The first examples of Diels-Alder reactions of chiral, C-2-symmetric (E,E)-1,4-dialkoxy-1,3-butadienes are described. The cycloadditions with maleic anhydride lead in all instances to the exclusive formation of the endo adducts. C-2h-Symmetric dienophiles such as fumaronitrile and diethyl fumarate react with variable diastereoselectivities; best results are obtained with the camphor-derived diene Id, whose reaction with diethyl fumarate takes place with complete facial selectivity. A theoretical analysis, using the SCF-MO procedure AM1, of the conformations of the dialkoxydienes has been used to rationalize the steric course of the cycloadditions. (C) 1999 Elsevier Science Ltd. All rights reserved.