Heterocycles from Morita–Baylis–Hillman adducts: synthesis of 5-oxopyrazolidines, arylidene-5-oxopyrazolidines, and oxo-2,5-dihydro-pyrazols
作者:José Tiago M. Correia、Manoel T. Rodrigues、Hugo Santos、Cláudio F. Tormena、Fernando Coelho
DOI:10.1016/j.tet.2012.10.057
日期:2013.1
Starting from Morita–Baylis–Hillman (MBH) adducts, an approach for the synthesis of oxopyrazolidines, arylidene-oxopyrazolidines, and oxo-2,5-dihydropyrazoles is described. The method is based on a tandem process involving a Michaeladdition of amino-guanidine into silylated and acetylated MBH adducts, followed by intramolecular cyclization. The use of acetylated MBH adducts led also to the synthesis
AN EASY CONVERSION OF THE BAYLIS-HILLMAN ADDUCTS INTO <i>tert-</i>BUTYLDIMETHYLSILYL ETHERS WITH <i>tert-</i>BUTYLDIMETHYLSILYL CHLORIDE AND Li<sub>2</sub>S
作者:Manouchehr Mamaghani、Abed Badrian
DOI:10.1080/10426500490485291
日期:2004.12.1
The hydroxy group of the Baylis-Hillman adducts is protected with the t-butyldimethylsilyl (TBDMS) group using the reaction of adducts 1a–h with tert-butyldimethylsilyl chloride (TBDMSCl) in the presence of lithium sulfide under nearly acidic reaction conditions.
Diastereoselective Epoxidation of Allylic Diols Derived from Baylis-Hillman Adducts
作者:Fernando Coelho、Ricardo S. Porto、Mario L. Vasconcellos、Elizete Ventura
DOI:10.1055/s-2005-872091
日期:——
The results of a highly diastereoselective epoxidation of allylic diols derived from Baylis-Hillman adducts are reported. The formation of an intramolecular hydrogen bond seems to be responsible for the high anti diastereoselection obtained in this epoxidation reaction. The results are complementary to those obtained in the direct epoxidation of Baylis-Hillman adducts, in which an elevated syn diastereoselectivity was observed.
Hyphenating the curtius rearrangement with Morita-Baylis-Hillman adducts: synthesis of biologically active acyloins and vicinal aminoalcohols
作者:Giovanni W. Amarante、Mayra Cavallaro、Fernando Coelho
DOI:10.1590/s0103-50532011000800022
日期:——
Ozonolysis of Morita–Baylis–Hillman adducts originated from aromatic aldehydes: an expeditious diastereoselective approach for the preparation of α,β-dihydroxy-esters
作者:Carlos A.M. Abella、Patrícia Rezende、Michele F. Lino de Souza、Fernando Coelho
DOI:10.1016/j.tetlet.2007.10.149
日期:2008.1
We disclose herein ozonolysis of Morita-Baylis-Hillman adducts originated from aromatic aldehydes. This efficient reaction provides alpha-ketoesters with different substitution patterns on the aromatic ring. Diastercoselective reduction of the corresponding alpha-ketoester obtained in the oxidative cleavage step provides alpha,beta-dihydroxy-esters with excellent degree of anti diastereoselection. The method is simple and easy to execute and is therefore a valuable alternative to prepare either alpha-ketoesters or alpha-dihydroxy-esters. (c) 2007 Elsevier Ltd. All rights reserved.