Regioselective synthesis of 5-alkylidene and 5-(iodoalkylidene)-pyrrol-2(5H)-ones by halolactamisation of (2Z,4E)-dienamides and (Z)-alk-2-en-4-ynamides
摘要:
Stereo- and regioselective synthesis of 5-alkylidene (arylidene) and 5-(iodoalkylidene)-pyrrol-2(5H)-ones was achieved from (2Z,4E)-dienamides and (Z)-alk-2-en-4-ynamides by halocyclisation reaction. Selectivity was found to be highly dependent on the nature of the substituents and on the tempetature. (C) 2001 Elsevier Ltd. All rights reserved.
A variety of substituted 5-alkyl(aryl)idene- and 5-[iodoalkyl(aryl)idene]-1H-pyrrol-2(5H)-ones were readily prepared with good yields under very mild reaction conditions by the iodocyclization of (2Z,4E)-dienamides and (Z)-alk-2-en-4-ynamides with iodine monochloride. 3-Ylidene-isoindolin-1-ones were also synthesized in moderate to good yields under the same conditions. The methodology proceeded with total regioselectivity in all cases and was applied to the synthesis of new unsaturated lactam compounds.
Regioselective rhodium-catalyzed intermolecular [2+2+2] cycloaddition of alkynes and isocyanates to form pyridones
作者:Kevin M. Oberg、Ernest E. Lee、Tomislav Rovis
DOI:10.1016/j.tet.2009.02.021
日期:2009.6
A highly regioselective rhodium-catalyzed intermolecular [2+2+2] cycloaddition of terminal alkynes with a variety of isocyanates to provide 2- and 4-pyridones has been developed. This reaction proceeds in good to excellent yields and overcomes the problem of dimerization and trimerization through the use of phosphoramidite ligands. A CO migration in the metallacycle is proposed to account for the formation of 4-pyridone. (C) 2009 Elsevier Ltd. All rights reserved.
Highly Efficient Access to Iminoisocoumarins and α-Iminopyrones via AgOTf-Catalyzed Intramolecular Enyne−Amide Cyclization
作者:Ming Bian、Weijun Yao、Hanfeng Ding、Cheng Ma
DOI:10.1021/jo9023478
日期:2010.1.1
Iminoisocoumarins and alpha-iminopyrones are prepared via Sonogashira coupling and AgOTf-catalyzed 6-endo-dig O-cyclization of the enyne-amide system in dichloroethane, in one pot or stepwise, respectively.
Regioselective synthesis of 5-alkylidene and 5-(iodoalkylidene)-pyrrol-2(5H)-ones by halolactamisation of (2Z,4E)-dienamides and (Z)-alk-2-en-4-ynamides
Stereo- and regioselective synthesis of 5-alkylidene (arylidene) and 5-(iodoalkylidene)-pyrrol-2(5H)-ones was achieved from (2Z,4E)-dienamides and (Z)-alk-2-en-4-ynamides by halocyclisation reaction. Selectivity was found to be highly dependent on the nature of the substituents and on the tempetature. (C) 2001 Elsevier Ltd. All rights reserved.