Conversion of allyl alcohols to 1,3-dienes by sequential sulfenate sulfoxide [2,3]-sigmatropic rearrangement and syn-elimination

Reich, Hans J.; Wollowitz, Susan

doi:10.1021/ja00389a028

Cited by 80 publications

(29 citation statements)

References 2 publications

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“…The 1 H NMR spectrum of this material corresponded to that obtained earlier. 9 mmol was added to a solution of 1-phenylcyclohexadiene (prepared by the method of Reich and Wollowitz; [46] 1.00 g, 6.44 mmol) in Et 2 O (50 mL) and heated under reflux for 20 h. After cooling, the mixture was filtered through Celite and evaporated. Flash chromatography on silica gel eluted with petroleum ether gave 23…”

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confidence: 99%

Selective Synthesis and Reactivity of η⁵‐Arylcyclohexadienyliron Complexes

Owen¹,

Malkov²,

Palotai³

et al. 2007

Chemistry A European J

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A series of aryl-substituted cyclohexadienyliron complexes have been prepared by a general procedure that determines regioselectivity by correctly positioning leaving groups in the precursor complexes. The aryl groups at 1-C or 2-C have been shown to be omega directing by the study of reactions with a representative range of nucleophiles, and these regioselectivity properties have been related to the spectroscopic properties of the cationic cyclohexadienyliron complexes. A high level of electron-donating substituents on the arene, or switching between the [Fe(CO)3] and [Fe(CO)2PPh3] series, reduces the minor ipso pathway, improving regiocontrol. Placing opposed directing groups in the arylcyclohexadienyliron complexes reverts reactivity to the ipso pathway with stabilised enolate nucleophiles, and when the additional directing group reinforces the effect of the aryl group, the ipso pathway is stopped.

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Selective Synthesis and Reactivity of η⁵‐Arylcyclohexadienyliron Complexes

Owen¹,

Malkov²,

Palotai³

et al. 2007

Chemistry A European J

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“…The only exceptions to this rule seem to be the alkyl p-nitrophenylsulfenates 7. [27,29,30] However, experimental difficulties have been observed in some instances upon photochemical generation of alkoxyl radicals from these compounds in synthetic reactions. [30] In type-II O-radical precursors (Figure 3), the radical oxygen atom is introduced into the alkyl residue by a separate nucleophilic substitution process (compounds 8Ϫ13), [31Ϫ35] or by insertion of an O 2 molecule (e.g.…”

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Stereoselective Construction of the Tetrahydrofuran Nucleus by Alkoxyl Radical Cyclizations

Hartung¹

2001

Eur. J. Org. Chem.

142

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Whereas carbon radical cyclizations have been applied for many years in the stereoselective synthesis of carbocyclic compounds, intramolecular C−O bond formations using alkoxyl radical reactions are less well understood. Since the discovery of N‐alkoxypyridine‐2(1H)‐thiones 8 as efficient sources of oxygen‐centered radicals, and the marked progress in the synthesis of these and related compounds which has been made in the last five years, however, a systematic study of O‐radical cyclizations under neutral conditions has become available. Kinetic experiments using the radical clock technique found that the parent 4‐penten‐1‐oxyl radical 1 undergoes an extremely fast 5‐exo‐trig ring‐closure [(4 ± 2) × 108 s−1 (30 °C)] which, after hydrogen trapping, selectively affords 2‐methyltetrahydrofuran (50). Tetrahydropyran (56), which originates from the slower 6‐endo‐trig cyclization, was observed in minor amounts. This observation pointed to a more diverse regioselectivity of O‐radicals in intramolecular addition reactions to olefinic double bonds than had been predicted from earlier experiments. A mechanistic study of ring‐closure reactions of the substituted 4‐penten‐1‐oxyl radicals 51 led to two major conclusions. Firstly, 1‐, 2‐, 3‐, and 5‐substituted radicals cyclize stereoselectively and 5‐exo‐trig‐regioselectively. The degree of stereoselectivity is governed by steric effects. To date, the only exceptions to this rule remain cyclizations of the para‐substituted 1‐aryl‐4‐penten‐1‐oxyl radicals 51e−m. These intermediates cyclize regioselectively, but not stereoselectively. Secondly, substituents at position 4 of the 4‐penten‐1‐oxyl radical are the key for controlling regioselectivities in O‐radical ring‐closure reactions. Thus, the 4‐phenyl‐4‐penten‐1‐oxyl radical 51u cyclizes 6‐endo‐trig‐selectively to afford, after hydrogen trapping, 2‐phenyltetrahydropyran (59u) as the major product (5‐exo:6‐endo = 5:95). Results from mechanistic and theoretical studies have been combined in order to derive a general model for predicting alkoxyl radical selectivities in ring closure reactions. The utility of this predictive device has recently been confirmed in the course of a new stereoselective synthesis of the central ring in muscarine alkaloid 72.

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“…Treatment of 10 with 2,4-dinitrobenzenesulfenyl chloride effected an allylic transposition and a subsequent sulfoxide elimination to provide enantioenriched diene 6. [17] As anticipated, the diboration/oxidation of 6 occurred with excellent levels of diastereoselection to provide diol 11 in 83 % yield. Notably, in comparison to the simple phenyl-derived substrate (entry 1, Table 1), this example shows that diene 6 is processed efficiently and without interference from the Lewis basic functionality in the substrate.…”

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A Boron‐Based Synthesis of the Natural Product (+)‐trans‐Dihydrolycoricidine

Poe¹,

Morken²

2011

Angewandte Chemie

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Conversion of allyl alcohols to 1,3-dienes by sequential sulfenate sulfoxide [2,3]-sigmatropic rearrangement and syn-elimination

Cited by 80 publications

References 2 publications

Selective Synthesis and Reactivity of η⁵‐Arylcyclohexadienyliron Complexes

Selective Synthesis and Reactivity of η⁵‐Arylcyclohexadienyliron Complexes

Stereoselective Construction of the Tetrahydrofuran Nucleus by Alkoxyl Radical Cyclizations

A Boron‐Based Synthesis of the Natural Product (+)‐trans‐Dihydrolycoricidine

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Conversion of allyl alcohols to 1,3-dienes by sequential sulfenate sulfoxide [2,3]-sigmatropic rearrangement and syn-elimination

Cited by 80 publications

References 2 publications

Selective Synthesis and Reactivity of η5‐Arylcyclohexadienyliron Complexes

Selective Synthesis and Reactivity of η5‐Arylcyclohexadienyliron Complexes

Stereoselective Construction of the Tetrahydrofuran Nucleus by Alkoxyl Radical Cyclizations

A Boron‐Based Synthesis of the Natural Product (+)‐trans‐Dihydrolycoricidine

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Selective Synthesis and Reactivity of η⁵‐Arylcyclohexadienyliron Complexes

Selective Synthesis and Reactivity of η⁵‐Arylcyclohexadienyliron Complexes