A New Strategy toward Indole Alkaloids Involving an Intramolecular Cycloaddition/Rearrangement Cascade
作者:Albert Padwa、Michael A. Brodney、Stephen M. Lynch、Paitoon Rashatasakhon、Qiu Wang、Hongjun Zhang
DOI:10.1021/jo049808i
日期:2004.5.1
The intramolecular Diels−Alder reaction between an amidofuran moiety tethered onto an indole component was examined as a strategy for the synthesis of Aspidosperma alkaloids. Furanyl carbamate 23 was acylated using the mixed anhydride 26 to provide amidofuran 22 in 68% yield. Further N-acylation of this indole furnished 27 in 88% yield. Cyclization precursors were prepared by removing the carbamate
Intramolecular Amidofuran Cycloadditions across an Indole π-Bond: An Efficient Approach to the <i>Aspidosperma</i> and <i>Strychnos</i> <i>ABCE</i> Core
作者:Stephen M. Lynch、Scott K. Bur、Albert Padwa
DOI:10.1021/ol027024q
日期:2002.12.1
[reaction: see text] The intramolecular Diels-Alder reaction between an amidofuran moiety tethered onto an indole component was examined as a strategy for the synthesis of Aspidosperma and Strychnos alkaloids. Furanyl carbamate 13 was acylated using the mixed anhydride 16 to provide amidofuran 12 in 68% yield. Further N-acylation of this indole furnished 17 in 88% yield. Cyclization precursors were
Application of Furanyl Carbamate Cycloadditions Toward the Synthesis of Hexahydroindolinone Alkaloids
作者:Albert Padwa、Michael A. Brodney、Martin Dimitroff、Bing Liu、Tianhua Wu
DOI:10.1021/jo010020z
日期:2001.5.1
been achieved by an intramolecular Diels--Alder cycloaddition reaction (IMDAF) of furanyl carbamates bearing tethered alkenyl groups. The initially formed [4 + 2]-cycloadduct undergoes nitrogen-assisted ring opening followed by deprotonation of the resulting zwitterion to give the rearranged ketone. The stereochemical outcome of the IMDAF cycloaddition has the sidearm of the tethered alkenyl group oriented
A Cycloaddition Approach toward the Synthesis of Substituted Indolines and Tetrahydroquinolines
作者:Albert Padwa、Michael A. Brodney、Bing Liu、Kyosuke Satake、Tianhua Wu
DOI:10.1021/jo982453g
日期:1999.5.1
acyl azide by a Curtius rearrangement in the presence of an alcohol. Alkylation of the resulting N-alkyl carbamate with an alkenyl bromide allows for the synthesis of a wide variety of cycloaddition precursors. The scope of the IMDAF reaction was evaluated by using mono- and disubstituted alkenes, electron rich and electron deficient olefins, and acetylenic tethers. Cyclic 2-amidofurans were also synthesized
Access to a Welwitindolinone Core Using Sequential Cycloadditions
作者:Barry M. Trost、Patrick J. McDougall
DOI:10.1021/ol901499b
日期:2009.8.20
A concise approach to the core skeleton of the welwitindolinone alkaloids was developed on the basis of sequential cycloaddition reactions. First, a palladium catalyzed enantioselective [6 + 3] trimethylenemethanecycloaddition onto a tropone nucleus was used to generate the requisite bicyclo[4.3.1]decadiene. Subsequent modifications to the cycloadduct allowed for an intramolecular [4 + 2] cycloaddition