Sultone rearrangements. II. Deuterated analogs of 10-isobornyl sultone. Exo-3,2-methyl shifts and discrete 2-norbornyl cations

Dimmel, Donald R.; Fu, Wallace Y.

doi:10.1021/jo00961a030

Cited by 10 publications

(6 citation statements)

References 3 publications

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“…49-~euteriocamphor (26) (16,19,(24)(25)(26)) and 8-deuteriocamphor (18) (19,26,27) were synthesized by reducing 9-bromocamphor (2) and 8-bromocamphor (4), respectively, with Bu3SnD/AIBN. Subsequent brornination ( l c ) then provided the corresponding 3,3-dibromo derivatives.…”

Section: Synthesis Of 8-bromocamphor (4): Evidence Formentioning

confidence: 99%

“…Subsequent brornination ( l c ) then provided the corresponding 3,3-dibromo derivatives. The almost exclusive occurrence of 3,2-exo rather than 3,2-endo methyl shifts in rearrangements involving bornyl or norbornyl carbocations has been thoroughly documented by several research groups (9)(10)(11)(12)(13)(14)(15)(16)(17), and a stereoelectronic effect (8,20,21) has been proposed to account for this stereoselectivity. The stereoelectronic effect can be illustrated in the case of camphene (47) racemization (cf.…”

Section: Synthesis Of 8-bromocamphor (4): Evidence Formentioning

confidence: 99%

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Formation of synthetically useful camphor derivatives: mechanistic aspects

Dadson¹,

Hutchinson²,

Money³

1990

Can. J. Chem.

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Section: Synthesis Of 8-bromocamphor (4): Evidence Formentioning

confidence: 99%

Section: Synthesis Of 8-bromocamphor (4): Evidence Formentioning

confidence: 99%

Formation of synthetically useful camphor derivatives: mechanistic aspects

Dadson¹,

Hutchinson²,

Money³

1990

Can. J. Chem.

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“…This new, effective resolving agent can easily be prepared on a large scale by the three-step sequence shown in Scheme from known isoborneol derivative 4 1 Synthesis of the Resolving Agent 9 a a Reagents and conditions: (a) TBSCl, Et 3 N, DMF, rt, 3 h; (b) SOCl 2 , C 6 H 6 , DMF; reflux 12 h; (c) NaN 3 , DMA, H 2 O, 60 °C 12 h, 57% isolated yield from 4 . …”

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confidence: 99%

A Novel Resolution Procedure for the Preparation of P-Stereogenic Phosphine Oxides

et al. 1999

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A new general route for preparing enantiomerically pure P-stereogenic phosphine oxides has been developed by exploiting the Staudinger reaction between racemic tertiary phosphines and an enantiomerically pure organoazide. The resulting phosphinimines are easily resolved by either crystallization or flash chromatography and serve as synthetic intermediates toward enantiomerically pure phosphine oxides.Asymmetric synthesis mediated by transition metals bearing enantiomerically pure phosphine ligands has become a cornerstone of organic chemistry and has allowed for the preparation of a variety of complex natural products. 1 As a result, much effort has been directed toward the rational design, synthesis, and testing of new enantiomerically pure phosphines for various synthetic purposes. A diverse range of enantiomerically pure phosphines is now commercially available, and numerous other ligands have been reported in the literature. 2 Among these known phosphines, however, the vast majority of examples are predicated upon carbonbased central or axial chirality rather than asymmetry about a tetrahedral phosphorus atom. The low abundance of P-stereogenic phosphines for asymmetric transformations is due, in part, to the relative difficulty of obtaining such compounds by resolution procedures or diastereoselective synthesis. 3 While there have been several recent advances in the diastereoselective synthesis of P-stereogenic materials, 4 there are still relatively few resolution methods available for obtaining enantiomerically pure tertiary phosphines. We herein report a new, simple, and effective method for obtaining P-stereogenic phosphine oxides using an enantiomerically pure organoazide resolving agent.We rationalized that a Staudinger reaction between a racemic tertiary phosphine and an enantiomerically pure azide could potentially furnish a 1:1 mixture of diastereomeric phosphinimines if the PdN bond rotational barrier was low enough to prevent geometrical isomerism. 5 To our delight, treatment of racemic phosphine 1a with (1S)-camphorsulfonyl azide 2 6 afforded an equimolar mixture of dia- †

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“…The letter was formed as a racemate ([α] D r.t. = 0, centrosymmetric space group ( P 2 1 / a ) of the single crystal used for X‐ray analysis). Although mechanistic investigations of the camphene sultone have been studied, we could, so far, not explain the formation of the closely related sultone 12 (and of 11 ) (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Structural Characterization of Novel Camphor‐derived Amines

et al. 2012

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Two novel 4-substituted camphidine derivatives 10a,b have been prepared from (+)-camphor (1) in five steps, the Beckmann rearrangement being the bottleneck of the synthesis. Isoborneol derivative 5b, formed as a side product during the hydrogenation of arylidene ketone 3b, under Beckmann rearrangement conditions yielded interesting novel rearrangement products 11 and 12. (1S)-(+)-Camphorquinone (13) was transformed into diamines 15 and 16 in two steps, the former being cyclized into an imidazoline salt 17, an N-heterocyclic carbene precursor. The structures of all novel compounds have been meticulously characterized using NMR techniques and/or single crystal X-ray analysis.

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Sultone rearrangements. II. Deuterated analogs of 10-isobornyl sultone. Exo-3,2-methyl shifts and discrete 2-norbornyl cations

Abstract: 133 (100), 117 (12), 105 (13), 91 (14), 77 (8), 51 (6), 41 (11), 39 (12), and 29 (12). The ir and nmr spectra were in complete agreement with those of 2,3-dimethylcumene. A vpc collected sample showed the same spectral properties.5

Cited by 10 publications

References 3 publications

Formation of synthetically useful camphor derivatives: mechanistic aspects

Formation of synthetically useful camphor derivatives: mechanistic aspects

A Novel Resolution Procedure for the Preparation of P-Stereogenic Phosphine Oxides

Synthesis and Structural Characterization of Novel Camphor‐derived Amines

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