Sequential Reactions Promoted by Manganese: Completely Stereoselective Synthesis of (E)-α,β-Unsaturated Amides, Ketones, Aldehydes, and Carboxylic Acids
摘要:
A complete E-selective synthesis of a,alpha,beta-unsaturated amides through a sequential reaction of a range of dichloroamides with a variety of aldehydes promoted by Rieke manganese (Mn*) is reported. A mechanism based on a sequential aldol-type reaction and a completely stereoselective beta-elimination is proposed to explain these results. The unsaturated amides obtained are readily and efficiently transformed into alpha,beta-unsaturated ketones, aldehydes, or carboxylic acids without loss of the diastereoisomeric purity of the C-C double bond.
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
CrCl<sub>2</sub>-Promoted Stereospecific and Stereoselective Alkyl- and Silylcyclopropanation of α,β-Unsaturated Amides
作者:José M. Concellón、Humberto Rodríguez-Solla、Carmen Méjica、Elena G. Blanco、Santiago García-Granda、M. Rosario Díaz
DOI:10.1021/jo800103t
日期:2008.5.1
An efficient chromium-promoted alkyl- or silylcyclopropanation of α,β-unsaturated amides is described. These reactions can be carried out on (E)- or (Z)-α,β-enamides in which the C−C double bond is di-, or trisubstituted. This process takes place with totalstereospecificity and the new stereogenic center is generated with high or total stereoselectivity. Some synthetic applications of the obtained
Sequential Reactions Promoted by Manganese: Completely Stereoselective Synthesis of (<i>E</i>)-α,β-Unsaturated Amides, Ketones, Aldehydes, and Carboxylic Acids
作者:José M. Concellón、Humberto Rodríguez-Solla、Pamela Díaz
DOI:10.1021/jo701417z
日期:2007.10.1
A complete E-selective synthesis of a,alpha,beta-unsaturated amides through a sequential reaction of a range of dichloroamides with a variety of aldehydes promoted by Rieke manganese (Mn*) is reported. A mechanism based on a sequential aldol-type reaction and a completely stereoselective beta-elimination is proposed to explain these results. The unsaturated amides obtained are readily and efficiently transformed into alpha,beta-unsaturated ketones, aldehydes, or carboxylic acids without loss of the diastereoisomeric purity of the C-C double bond.
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