Synthesis and Reactions of <i>exo</i>-Camphorylsulfonyloxaziridine

Davis, Franklin A.; Reddy, Rajarathnam E.; Kasu, P. V. N.; Portonovo, Padma; Carroll, Patrick J.

doi:10.1021/jo961991v

Cited by 21 publications

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References 17 publications

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“…Since the data reported for 4a,b did not mention any 13 C-NMR multiplicities or 1 H-NMR Overhauser experiments [12a], we had some difficulty to assign the signals and thus performed these supplementary analyses to determine the conformation of 4b in solution 26 ). This structure shows a pseudo-equatorial FÀN bond (FÀNÀC(2)ÀC (1) 24 ) The conformational attribution is based on 19 F-NMR coupling constant analysis by comparison with the purely pseudo-equatorial N-fluoro-3,3-dichloro analogue of (À)-1c as exhibited by its X-ray-structural analysis [33]. 85 (2002) 1980 22 ) We are indebted to Drs.…”

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“…Cieplak also proposed a hyperconjugative influence of the N lp on the incipient bond-formation through the intermediacy of a sp 2 atom, see Schemes 85 and 86 as well as reference 105 in [11]. For a bornanesulfonimide possessing a six-membered ring connected to C(2) and C(3), see [24]. We now wish to report the synthesis of the tricyclic six-membered-ring sultam (À)-3a as well as its X-ray-structural analysis for comparison with those of (À)-1a,b,e and the racemic six-membered-ring trans-decalin-like sultams 4a,b [12a].…”

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“…85 (2002) 1974 3 ) According to [15], a lower chemical yield was obtained by direct hydroboration of the unprotected ketone ()-6. For a bornanesulfonimide possessing a six-membered ring connected to C(2) and C(3), see [24]. 5 ) For cyclization under acidic conditions, see [19].…”

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“…16 ) This estimation is based on the knowledge that the Ph substituent in sultam 4c adopts an equatorial orientation according to X-ray structural analysis [31] and that the K value for Ph in a cyclohexane ring is 209, corresponding to a difference of 3.0 kcal/mol [32]. He also found that at À 668 this mixture consists of a 3 : 97 ratio of the pseudo-axial/equatorial conformers 24 ). The C(1)ÀC(2)ÀN angle is 103.9(3)8 for (À)-1a as compared to 115. .…”

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Synthesis of a Six-Membered-Ring (2R)-10a-Homobornane-10a,2-sultam and Structural Comparison with Oppolzer's, Lang's, and King's Sultams

Piątek¹,

Chapuis²,

Jurczak³

2002

HCA

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The new six-membered-ring (2R)-10a-homobornane-10a,2-sultam (À)-3a was synthesized and its X-ray structural analysis was compared with that of the novel structure of the five-membered-ring (2R)-bornane-10,2sultam analogues (À)-1a,b as well as with that already published for the six-membered-ring trans-decalin-like sultam 4a. Based on DN** density-function calculations and X-ray crystallographic studies of the N-methylated analogues (À)-1e and 4b and by comparing with the conformation of the N-fluoro derivatives (À)-1c and ()-1d, the anomeric stabilization was estimated to be smaller than the 2.0 ± 2.5 kcal/mol earlier suggested. The direction of pyramidalization is rationalized in terms of H-bond and steric and electronic interactions and extended to the known toluenesultam derivatives 10a ± c. 2 ) For N lp through-bond and through-space directing interactions, initially suggested by M¸ller and Eschenmoser, see [10a]. For nonexhaustive more recent examples, see [10b ± g]. Cieplak also proposed a hyperconjugative influence of the N lp on the incipient bond-formation through the intermediacy of a sp 2 atom, see Schemes 85 and 86 as well as reference 105 in [11]. More recently, King et al. also suggested an anomeric stabilization [12a]. We now wish to report the synthesis of the tricyclic six-membered-ring sultam (À)-3a as well as its X-ray-structural analysis for comparison with those of (À)-1a,b,e and the racemic six-membered-ring trans-decalin-like sultams 4a,b [12a].Results. ± The commercially available ()-camphorsulfonyl chloride 5 was treated with CH 2 N 2 in Et 2 O to afford, after thermal treatment, the known unsaturated C 11 ketone ()-6 in 84% yield according to a previously reported procedure [13]. Further protection of the carbonyl moiety (ethylene glycol, TsOH, THF; 79% yield) followed by hydroboration (9-BBN, THF, 208, then NaOH, H 2 O 2 ; 90% yield) furnished the known primary alcohol (À)-7a [14] 3 ). This intermediate was then converted to the corresponding crude unreported mesylate (À)-7b (MsCl, CH 2 Cl 2 , Et 3 N, 08; 95% yield [16]) prior to an S N 2 displacement (AcSK, DMSO, 458; 96% yield [17]) to afford the thioacetate (À)-7c. Oxidation (30% H 2 O 2 solution, 85%, AcOH solution [18]), with concomitant deprotection, delivered the new sulfonic acid ()-8a in 92% isolated yield. A route similar to that earlier published by Oppolzer et al.[1] was then followed for the preparation of (À)-3a.Thus, treatment with SOCl 2 at 1008 [19] furnished the sulfonyl chloride (À)-8b in 63% yield 4 ). Rather than addition of gaseous NH 3 under anhydrous conditions [21], we preferred, for technical reasons, the NH 4 OH procedure initially reported by Sutherland and co-workers [22] and recently re-actualized by Davis et al. [19] and Capet et al. [23]. The new sulfonamide ()-8c, thus obtained in 69% yield, was then cyclized under basic conditions (NaOMe, MeOH [1]) to furnish the sulfonimine (À)-9 in 75% yield 5 ).Helvetica Chimica Acta ± Vol. 85 (2002) 1974 3 ) According to [15], a lower chemical yield was obtaine...

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Synthesis of a Six-Membered-Ring (2R)-10a-Homobornane-10a,2-sultam and Structural Comparison with Oppolzer's, Lang's, and King's Sultams

Piątek¹,

Chapuis²,

Jurczak³

2002

HCA

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“…In contrast, oxaziridines ( III-O ) constitute a class of strained heterocycles exhibiting a remarkable stability. Therefore, they are much less reactive in oxidation reactions compared to dioxiranes ( I-O ) and oxaziridinium salts ( II-O ) – and, depending on the substituents, show a different reactivity such as electrophilic amination . However, the relatively inert oxaziridines III-O have been activated by Lewis acids to achieve the selective oxidation of sulfides .…”

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Novel N-Phosphonio Imine-Catalyzed Epoxidation Reactions

et al. 2008

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α‐Hydroxylation of Enolates and Silyl Enol Ethers

et al. 2003

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The autoxidation of enolizable carbonyl compounds was reported as early as 1871, and the accelerating action of base is well documented. The products of these reactions, however, were usually mixtures of compounds resulting from decomposition of the unstable alpha‐hydroperoxy intermediates. It was not recognized until the 1960s that these intermediates can be reduced to alpha‐hydroxy compounds with zinc dust. This observation laid the foundation for what has become on of the simplest and most widely used strategies for introducing a hydroxyl group adjacent to a carbonyl group, namely the oxidation of metal enolates. The alpha‐hydroxy carbonyl array not only occurs in many biologically active molecules, but also serves as an important building block for synthesis. While the oxygenation of enolates still play an important role in the synthesis of alpha‐hydroxy carbonyl compounds, a variety of new, more convenient oxididizing agents, including chiral nonracemic ones, have been introduced. In addition, sily enol ethers and silyl ketene acetals can serve as educts for alpha‐hydroxycarbonyl compounds. This chapter covers the literature of alpha‐hydroxylation of metal enolates and silyl enol ethers up to the end of 2000. Nitriles and aza‐enolates are included. The related alpha‐alkoxylation, alpha‐acyloxylation, and alpha‐sulfonyloxylation of metal enolates are briefly discussed.

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Synthesis and Reactions of exo-Camphorylsulfonyloxaziridine

Cited by 21 publications

References 17 publications

Synthesis of a Six-Membered-Ring (2R)-10a-Homobornane-10a,2-sultam and Structural Comparison with Oppolzer's, Lang's, and King's Sultams

Synthesis of a Six-Membered-Ring (2R)-10a-Homobornane-10a,2-sultam and Structural Comparison with Oppolzer's, Lang's, and King's Sultams

Novel N-Phosphonio Imine-Catalyzed Epoxidation Reactions

α‐Hydroxylation of Enolates and Silyl Enol Ethers

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