Intermolecular and intramolecular reactions of resolved 2-alkoxytetrahydrofuran-3-yl and 2-alkoxytetrahydropyran-3-yl radicals

Kalpana S. Nimkar, Eugene A Mash

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Diastereomeric trans-2-alkoxy-3-phenylselenenyltetrahydrofuranyl acetals and trans-2-alkoxy-3-phenyl-selenenyltetrahydropyranyl acetals were prepared from dihydrofuran, dihydropyran, phenylselenenyl bromide, and the alcohols (S)-methyl lactate, (S)-methyl hexahydromandelate, and (R)-pantolactone. The diastereomers were chromatographically separated and were subjected to intermolecular alkylation via generation and trapping of free radicals. Observed diastereoselectivity was higher for 2-alkoxytetrahydrofuran-3-yl radicals than for 2-alkoxytetrahydropyran-3-yl radicals, and highest for acetals involving (R)-pantolactone. Alcohol exchanges at the anomeric carbon were highly stereocontrolled, and permitted introduction of alkenes for intramolecular trapping of free radical intermediates. (C) 2000 Elsevier Science Ltd.

Original languageEnglish (US)
Pages (from-to)5793-5800
Number of pages8
JournalTetrahedron
Volume56
Issue number32
StatePublished - Aug 4 2000

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Acetals
Free Radicals
Alcohols
Alkylation
Alkenes
Bromides
Carbon
pantolactone
alkoxyl radical

Keywords

  • Diastereoselection
  • Radicals and radical reactions
  • Resolution
  • Selenoacetals

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry
  • Drug Discovery

Cite this

Intermolecular and intramolecular reactions of resolved 2-alkoxytetrahydrofuran-3-yl and 2-alkoxytetrahydropyran-3-yl radicals. / Nimkar, Kalpana S.; Mash, Eugene A.

In: Tetrahedron, Vol. 56, No. 32, 04.08.2000, p. 5793-5800.

Research output: Contribution to journalArticle

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AB - Diastereomeric trans-2-alkoxy-3-phenylselenenyltetrahydrofuranyl acetals and trans-2-alkoxy-3-phenyl-selenenyltetrahydropyranyl acetals were prepared from dihydrofuran, dihydropyran, phenylselenenyl bromide, and the alcohols (S)-methyl lactate, (S)-methyl hexahydromandelate, and (R)-pantolactone. The diastereomers were chromatographically separated and were subjected to intermolecular alkylation via generation and trapping of free radicals. Observed diastereoselectivity was higher for 2-alkoxytetrahydrofuran-3-yl radicals than for 2-alkoxytetrahydropyran-3-yl radicals, and highest for acetals involving (R)-pantolactone. Alcohol exchanges at the anomeric carbon were highly stereocontrolled, and permitted introduction of alkenes for intramolecular trapping of free radical intermediates. (C) 2000 Elsevier Science Ltd.

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