Sequenced elimination–reduction and elimination–cyclopropanation reactions of 2,3-epoxyamides promoted by samarium diiodide. Synthesis of 2,3-dideuterioamides and cyclopropanamides
摘要:
An easy and general sequenced elimination/reduction or elimination/cyclopropanation process promoted by samarium diiodide or/and CH2I2/Sm provide an efficient method for synthesising 2,3-dideuterioamides 3 or cyclopropanamides 8, respectively. The transformations take place in high yields and with total or high selectivity from the easily available 2,3-epoxyamides. (C) 2004 Elsevier Ltd. All rights reserved.
Sequenced elimination–reduction and elimination–cyclopropanation reactions of 2,3-epoxyamides promoted by samarium diiodide. Synthesis of 2,3-dideuterioamides and cyclopropanamides
摘要:
An easy and general sequenced elimination/reduction or elimination/cyclopropanation process promoted by samarium diiodide or/and CH2I2/Sm provide an efficient method for synthesising 2,3-dideuterioamides 3 or cyclopropanamides 8, respectively. The transformations take place in high yields and with total or high selectivity from the easily available 2,3-epoxyamides. (C) 2004 Elsevier Ltd. All rights reserved.
Stereoselective Olefination Reactions Promoted by Rieke Manganese
作者:José Concellón、Humberto Rodríguez-Solla、Vicente del Amo、Pamela Díaz
DOI:10.1055/s-0029-1216880
日期:2009.8
applied to develop a novel and direct synthesis of (E)-α,β-unsaturated esters or amides and (Z)-α,β-unsaturated α-halo esters and α-choroamides through a Mn*-mediated sequential olefination protocol of aldehydes with dichloro esters or amides and trihalo esters or trichloroamides, respectively. manganese - elimination reactions - stereoselectivity - α,β-unsaturated esters - α,β-unsaturated amides - metalation
Stereospecific Cyclopropanation of Highly Substituted C−C Double Bonds Promoted by CrCl<sub>2</sub>. Stereoselective Synthesis of Cyclopropanecarboxamides and Cyclopropyl Ketones
作者:José M. Concellón、Humberto Rodríguez-Solla、Carmen Méjica、Elena G. Blanco
DOI:10.1021/ol070896d
日期:2007.8.1
(Z)-alpha,beta-enamides in which the C-C double bond is di-, tri-, or tetrasubstituted. In all cases the process is completely stereospecific and only a single diastereoisomer is obtained. In addition, cyclopropyl ketones were readily prepared by reaction of the cyclopropanecarboxamides (derived from morpholine) obtained with a range of organolithium compounds. A mechanism has been proposed to explain the cyclopropanation
Manganese-Promoted Regioselective Ring-Opening of 2,3-Epoxy Acid Derivatives: A New Route to α-Hydroxy Acid Derivatives
作者:José M. Concellón、Pablo L. Bernad、Humberto Rodríguez-Solla、Pamela Díaz
DOI:10.1002/adsc.200900257
日期:2009.9
amides as starting materials, the corresponding 3-aryl-2-hydroxy amides in enantiopure form are also available. Some synthetic applications of selected examples of 3-aryl-2-hydroxy carboxylic acidderivatives are shown. A mechanism has been proposed to explain this novel reaction.
Highly Stereoselective Halocyclopropanation of α,β-Unsaturated Amides
作者:José M. Concellón、Humberto Rodríguez-Solla、Elena G. Blanco、María A. Villa-García、Noemí Alvaredo、Santiago García-Granda、M. Rosario Díaz
DOI:10.1002/adsc.200900331
日期:2009.9
A convenient highly stereoselective synthesis of chloro- and bromocyclopropanamides from di- tri- or tetrasubstituted (E)- or (Z)-α,β-unsaturatedamides with total or high stereoselectivity promoted by chromium dichloride or dibromide is described. The transformation of chlorocyclopropanamides into the corresponding ketones or amines is also reported. A mechanism to explain these transformations is