Intramolecular insertion of arylsulfonylnitrenes into aliphatic side chains

Abramovitch, R. A.; Chellathurai, T.; Holcomb, William D.; MCMASTER, I. T.; Vanderpool, Danny P.

doi:10.1021/jo00437a030

Cited by 20 publications

(8 citation statements)

References 20 publications

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“…All reactions were carried out under argon. Solvents were distilled by standard procedures prior to use, and the following compounds were prepared by published methods: P(NMeCH 2 CH 2 ) 3 N ( 1 ),3b P(NPr i CH 2 CH 2 ) 3 N ( 2 ), MeC(CH 2 NMe) 3 P ( 7 ), OP(CH 2 NMe) 3 P ( 8 ), 4-toluenesulfonyl azide, 2,4,6-trimethylbenzenesulfonyl azide, and the triamine MeC(CH 2 NMeH) 3 that was used to prepare 7 . It may be noted that 1 and 2 are available from Aldrich.…”

Section: Methodsmentioning

confidence: 99%

Reactions of Tris(amino)phosphines with Arylsulfonyl Azides: Product Dependency on Tris(amino)phosphine Structure

2002

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The Staudinger reaction of N(CH2CH2NR)3P [R = Me (1), Pr (2)] with 1 equiv of N3SO2C6H4Me-4 gave the ionic phosphazides [N(CH2CH2NR)3PN][SO2C6H4Me-4] [R = Me (3), R = Pr (5a)], and the same reaction of 2 with N3SO2C6H2Me3-2,4,6 gave the corresponding aryl sulfinite 5b. On the other hand, the reaction of 1 with 0.5 equiv of N3SO2Ar (Ar = C6H4Me-4) furnished the novel ionic phosphazide [[N(CH2CH2NMe)3P]2(mu-N3)][SO2Ar] (6). Data that shed light on the mechanistic pathway leading to 3 were obtained by low temperature 31P NMR spectroscopy. A crystal and molecular structure analysis of the phosphazide sulfonate [N(CH2CH2NMe)3PN3][SO3C6H4Me-4] (4), obtained by atmospheric oxidation of 3, indicated an ionic structure, the cationic part of which is stabilized by a transannular P-N bond. A crystal and molecular structure analysis of 6 also indicated an ionic structure in which the cation features two untransannulated N(CH2CH2NMe)3P cages bridged by an azido group in an eta 1: mu: eta 1 fashion. The reaction of P(NMe2)3 with N3SO2Ar (Ar = C6H4Me-4) in a 1:0.5 molar ratio furnished [[(Me2N)3P]2(mu-N3)][SO2-Ar] (11) in quantitative yield. On the other hand, the same reaction involving a 1:1 molar ratio of P(NMe2)3 and N3SO2Ar produced a mixture of 11, [(Me2N)3PN3][SO2Ar] (12), and the iminophosphorane (Me2N)3P=NSO2Ar (10). In contrast, the bicyclic tris(amino)phosphines MeC(CH2NMe)3P (7) and O=P(CH2NMe)3P (8) reacted with N3SO2-Ar (Ar = C6H4Me-4) to give the iminophosphorane MeC(CH2NMe)3P=NSO2Ar (14) (structured by X-ray means) and O=P(CH2NMe)3P=NSO2Ar (16) via the intermediate phosphazides MeC(CH2NMe)3PN3SO2Ar (13) and O=P(CH2NMe)3PN3SO2Ar (15), respectively. The variety of products obtained from the reactions of arylsulfonyl azides with proazaphosphatranes (1 and 2), acyclic P(NMe2)3, bicyclic tris(amino)phosphines 7 and 8 are rationalized in terms of steric and basicity variations among the phosphorus reagents.

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Section: Methodsmentioning

confidence: 99%

Reactions of Tris(amino)phosphines with Arylsulfonyl Azides: Product Dependency on Tris(amino)phosphine Structure

2002

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“…We additionally examined the cyclization of several 2‐alkyl‐substituted derivatives other than 2‐ethyl‐substituted ones (Table 3). To our surprise, the reaction of 2,5‐dicyclohexylbenezenesulfonyl azide ( 8 j ) primarily occurred not at the expected benzylic (α) position but at the homobenzylic (β) position to give the six‐membered sultam 10 j with high enantioselectivity (entry 1) 19. 20 To estimate the effect of the steric crowding around the CH bond on the regioselectivity, we examined the reaction of 2,5‐di‐ n ‐propylbenzenesulfonyl azide ( 8 k ).…”

Section: Methodsmentioning

confidence: 92%

Enantioselective Intramolecular Benzylic CH Bond Amination: Efficient Synthesis of Optically Active Benzosultams

et al. 2011

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Cyclic amine structures can be found in many biologically active compounds and their stereochemistry often has a significant effect on their biological activities. Enantioselective CÀN bond formation is a useful tool for synthesizing those compounds. Although various C À N bond-forming reactions are now known, C À H bond amination is highly atom efficient and it is of wide applicability because most organic compounds have CÀH bonds. Thus, regio-and stereoselective CÀH bond amination has attracted a growing amount of attention. [1] In addition, remarkable progress has recently been made in metal-catalyzed CÀH bond amination, particularly through metal nitrenoid insertion reactions. [2] Most of these C À H bond aminations, however, require Narenesulfonyliminophenyliodinane or related compounds to serve as the nitrene precursor and, furthermore, the atom efficiency of these particular reactions remains at an unsatisfactory level. Therefore, the establishment of a method for enantioselective C À H bond amination using an atom-efficient nitrene precursor such as an azide compound has become an increasingly common topic for research. [3] Seminal studies by Cenini and co-workers showed the potential of transitionmetal catalysis for CÀH bond amination using azide compounds. [4] Moreover, subsequent studies by Zhang and coworkers [5] and Driver and co-workers [6] demonstrated that intramolecular C À H bond amination catalyzed by a cobalt or an iridium complex is an efficient, though non-enantioselective, method of preparing heterocyclic compounds. Enantiopure sultams [7] have been used as chiral auxiliaries [8] and as key intermediates for the synthesis of HIV-1 reverse transcriptase [9] and COX-2 inhibitors. [10] An asymmetric version of the intramolecular C À H bond amination with arenesulfonyl azide [5a] could be an effective tool for the enantioselective synthesis of sultams, but the asymmetric version has not yet been reported.We recently reported that a ruthenium(CO)-salen complex catalyzed the enantioselective intermolecular allylic C À H bond amination using p-toluenesulfonyl azide with moderate to good enantioselectivity at room temperature (up to 80 % ee), albeit with low to moderate yields. [11] In contrast, we have recently demonstrated that iridium(III)-salen complexes are efficient catalysts for diastereo-and enantioselective carbenoid addition such as cyclopropanation, cyclopropenation, [12] and carbenoid C À H or Si À H bond insertion [13] using diazo compounds as the carbenoid precursors. Since diazo and azide compounds, and metal-carbenoid and nitrenoid intermediates are isoelectronic with one another, respectively, we expected that the iridium-salen complexes would serve as catalysts for asymmetric nitrenoid C À H bond insertion. Herein, we describe the enantioselective intramolecular C À H bond amination of sulfonyl azide compounds using an iridium-salen complex as the catalyst.Complexes 1-7 [14c] (Figure 1) were readily prepared from binol, an aryl halide, N,N-dimethylformamide, a diamine, and an ...

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“…Thermally generated nitrene 16 from sulfonyl azide 15 affords sultam 17 via intramolecular C-H insertion to the ortho-methyl group in 10-15% yields, because of the buttressing effects of the meta-methyl groups. 27 Reaction of tetramethylbenzenesulfonamide 18 with difluoro-l 3 -bromane 4, however, produced a high yield (85%) of Hofmann rearrangement product sulfamoyl fluoride 19 selectively and no formation of sultam 17 was detected in the reaction.…”

Section: Hofmann Rearrangement Of Arylsulfonamidesmentioning

confidence: 98%

Hypervalent N-sulfonylimino-λ3-bromane: active nitrenoid species at ambient temperature under metal-free conditions

et al. 2010

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The synthesis and reactions of N-triflylimino-lambda(3)-bromane are summarized. The hypervalent iminobromane functions as a highly active nitrenoid species at ambient temperature under transition metal-free conditions, probably because of the increased hypernucleofugality of aryl-lambda(3)-bromanyl groups compared to that of aryl-lambda(3)-iodanyl groups. The imino-lambda(3)-bromane undergoes stereospecific aziridination of olefins and transylidation to aromatic nitrogen heterocycles, trialkylamines and iodobenzenes. Difluoro-lambda(3)-bromane-induced Hofmann rearrangement of primary arylsulfonamides is also discussed.

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Intramolecular insertion of arylsulfonylnitrenes into aliphatic side chains

Cited by 20 publications

References 20 publications

Reactions of Tris(amino)phosphines with Arylsulfonyl Azides: Product Dependency on Tris(amino)phosphine Structure

Reactions of Tris(amino)phosphines with Arylsulfonyl Azides: Product Dependency on Tris(amino)phosphine Structure

Enantioselective Intramolecular Benzylic CH Bond Amination: Efficient Synthesis of Optically Active Benzosultams

Hypervalent N-sulfonylimino-λ3-bromane: active nitrenoid species at ambient temperature under metal-free conditions

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