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Journal ArticleDOI

Regioselective reductive: Elimination of aryloxymethylethynylcarbinols - synthesis of aryloxymethylallenes

01 Jan 1986-Tetrahedron Letters (Pergamon)-Vol. 27, Iss: 32, pp 3777-3780
TL;DR: In this paper, the exclusive formation of allenes and alkenols during the reduction of aryloxymethylethynylcarbinols and ethynyl carbinols respectively, with lithium aluminiumhydride, is reported.
About: This article is published in Tetrahedron Letters.The article was published on 1986-01-01. It has received 6 citations till now. The article focuses on the topics: Reductive elimination.
Citations
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Journal ArticleDOI
TL;DR: In this article, a review of recent advances in the direct transformation of propargylic alcohols to allenes is presented, which can be divided into four categories according to their reaction types: (1) reactions with transition metal catalysis, (2) reactions involving carbocation intermediates, (3) reactions that are metal hydride (base)-mediated, and (4) reaction involving oxa-propargyric intermediates.
Abstract: Allenes are the simplest class of cumulenes, possessing unique physical and chemical properties. These structural units are widely used as valuable synthetic intermediates in organic synthesis, as well as the key skeletons of many natural products, biologically active molecules, and pharmaceutical compounds. In recent decades, the development of synthetic methodologies for the synthesis of allenes by direct transformation of propargylic alcohols has attracted considerable attention among organic chemistry researchers. In this review, we focus on recent advances in the direct transformation of propargylic alcohols to allenes. These transformations can be divided into four categories according to their reaction types: (1) reactions with transition metal catalysis; (2) reactions involving carbocation intermediates; (3) reactions that are metal hydride (base)-mediated; and (4) reactions involving oxa-propargylic intermediates.

22 citations

Journal ArticleDOI
TL;DR: Reductive deoxyallenylation of sterically hindered tertiary propargylic alcohols was realized on reaction with 2-nitrobenzenesulfonylhydrazide (NBSH) by the combined use of Lewis and Brønsted acid catalysts, and affords various mono-, di-, and trisubstituted allenes in good-to-excellent yields.
Abstract: Reductive deoxyallenylation of sterically hindered tertiary propargylic alcohols was realized on reaction with 2-nitrobenzenesulfonylhydrazide (NBSH) by the combined use of Lewis and Bronsted acid catalysts. This method features a broad substrate scope, mild reaction conditions, and good functional-group tolerance, and affords various mono-, di-, and trisubstituted allenes in good-to-excellent yields. The synthetic utility of this method was demonstrated by the synthesis of 2H-chromenes and 1,2-dihydroquinolines.

18 citations

Book ChapterDOI
01 Jan 1995

15 citations

Book ChapterDOI
TL;DR: This chapter covers most of the allene and cumulene preparation methods including a brief highlight of the oldest and most efficient procedures, and focuses on novel and improved procedures based on CH, CC, and CC bond formation.
Abstract: Many synthetic methods, most of which are based on catalytic reactions, are now available to transform allene derivatives into useful organic compounds. Consequently, the need for allenes as starting compounds has led to the rapid development of efficient new syntheses. This chapter covers most of the allene and cumulene preparation methods including a brief highlight of the oldest and most efficient procedures, and focuses on novel and improved procedures based on CH, CC, and CC bond formation. It complements the chapter which was published in COFGT (1995) with new references.

10 citations

Journal ArticleDOI
TL;DR: A carboxyl-containing iron catalyst (FeII-DCBPY, DCBPY = 2,2′-bipyridine-4,4′-dicarboxylic acid), which could activate the C-H bonds of cycloalkanes with high secondary (2°) bond selectivity, was reported in this paper.
Abstract: In this work, we report the discovery of a carboxyl-containing iron catalyst 1 (FeII-DCBPY, DCBPY = 2,2′-bipyridine-4,4′-dicarboxylic acid), which could activate the C–H bonds of cycloalkanes with high secondary (2°) C–H bond selectivity. A turnover number (TN) of 11.8 and a 30% yield (based on the H2O2 oxidant) were achieved during the catalytic oxidation of cyclohexane by 1 under irradiation with visible light. For the transformation of cycloalkanes and bicyclic decalins with both 2° and tertiary (3°) C–H bonds, 1 always preferred to oxidise the 2° C–H bonds to the corresponding ketone and alcohol products; the 2°/3° ratio ranged between 78/22 and >99/1 across 7 examples. 18O isotope labelling experiments, ESR experiments, a PPh3 method and the catalase method were used to characterize the reaction process during the oxidation. The success of 1 showed that, in addition to using a bulky catalyst, high 2° C–H bond selectivity could also be achieved using a less bulky molecular iron complex as the catalyst.

7 citations

References
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Journal ArticleDOI
TL;DR: In this paper, the mechanism of the allene-forming reaction is discussed and the reduction of (R)-(+)-2,3,3-trimethylhex-4-yn-3-ol (3) in diglyme gave
Abstract: Lithium aluminium hydride reduction of (R)-(+)-2,3,3-trimethylhex-4-yn-3-ol (3) in diglyme gave(S)-(-)-4,5,5-trimethylhexa-2,3-diene (4) and (S)-(+)-(E)-2,3,3-trimethylhex-4-en-3-ol (5). The mechanism of the allene-forming reaction is discussed.

11 citations

Journal ArticleDOI
TL;DR: In this article, a reduction of 1,1-diphenylbut-2-yn-1-ol in diethyl or diisopropyl ether was shown to yield 1.
Abstract: Lithium aluminium hydride reduction of 1,1-diphenylbut-2-yn-1-ol in diethyl or diisopropyl ether gave 1,1-diphenylbuta-1,2-diene (4) and the (Z)- and (E)-1,1-diphenylbut-2-en-1-ols (5) and (6), but reaction in tetrahydrofuran solution gave only the (E)-alkenol (6).

7 citations