Solid‐Phase Synthesis of Dihydropyrans by Heterocycloaddition of a Supported Vinyl Ether: Progress in Functional Diversity

Abstract

The carboxypolystyrene‐bound vinyl ether of 1,4‐butanediol smoothly underwent an efficient endo‐selective hetero‐Diels−Alder reaction, under Lewis‐acid conditions, with heterodienes bearing methyl ester, trifluoromethyl and para‐tolylsulfinylmethyl groups at the C‐2 position. Reductive cleavage of the supported adducts afforded functionalized dihydropyrans, which are of particular interest for diversity‐oriented parallel synthesis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Advances in Solid-Phase Cycloadditions for Heterocyclic Synthesis

“…Reductive cleavage of the supported adducts afforded functionalized dihydropyrans, which are particularly interesting for combinatorial synthesis (Scheme 31). 45 The biomimetic synthesis of carpanone, first accomplished by Chapman, involves diastereoselective oxidative homocoupling of an electron-rich o-hydroxystyrene followed by rapid, endo-selective, inverse electron-demand Diels-Alder cycloaddition. 46 To construct a library of carpanone analogues, Lindsley et al expanded on the original chemistry to include intermolecular oxidative heterodimerization of o-hydroxystyrenes.…”

“…Resin-bound dienophiles, including the carboxypolystyrene-bound vinyl ether of 1,4-butanediol, have been used in efficient, endo-selective hetero-Diels−Alder reactions under Lewis-acid conditions with heterodienes bearing methyl ester, trifluoromethyl, and p -tolylsulphinylmethyl groups at the C-2 position. Reductive cleavage of the supported adducts afforded functionalized dihydropyrans, which are particularly interesting for combinatorial synthesis (Scheme ) …”

Hydroalkoxylation of alkynes by a nitroxyl containing alcohol, 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl: synthesis of spin-labeled enol ethers

“…For these considerations, the design of new TEMPO-based spin labels bearing appropriate chemically active linkers is a synthetic challenge. An attractive route to functionalization of the TEMPO skeleton might be the introduction into its molecule of the enol ether (vinyloxy) moiety that, thanks to its rich chemistry, [18][19][20][21] can be easily linked with the desired molecules such as sugars, amino acids, proteins, DNA, etc. Furthermore, the presence of easily polymerizable vinyloxy groups 22,23 in the molecules of paramagnetic compounds considerably extends their possible application in advanced technologies.…”

Comprehensive Survey of Combinatorial Library Synthesis: 2003

“…All entries are referenced by the first author's last name to facilitate reference cross-checking. Some 468 total entries are captured in the tables. − <...…”