Imines sulfonyl

Saito has recently reported high yields and enantioselectivities in aziridine synthesis through reactions between aryl- or vinyl-substituted N-sulfonyl imines and aryl bromides in the presence of base and mediated by a chiral sulfide 122 (Scheme 1.41) [66]. Aryl substituents with electron-withdrawing and -donating groups gave modest transxis selectivities (around 3 1) with high enantioselectiv-... 

In addition, the same group has used copper complexes of these ligands as efficient catalysts for enantioselective Cu-catalysed aza-Diels-Alder reactions of A-sulfonyl imines with Danishefsky s dienes, providing the corresponding six-membered heterocycles with enantioselectivities of up to 80% ee. ... 

Scheme 10.34 Cu-catalysed Mannich-type reactions of A -sulfonyl imines with Fes-ulphos ligand.

The reaction of alkynyllithium compounds with alkoxycarbene tungsten complexes leads to anionic propargyl tungsten complexes (Figure 2.33 see also Figure 3.9). These intermediates are stable at low temperatures and react upon Lewis acid catalysis with aldehydes or A -sulfonyl imines to yield five-membered heterocycles [280]. Oxidative methoxycarbonylation [375] of the intermediate vinyl tungsten complex, followed by elimination of methanol leads to pyrroles or furanes (Figure 2.33 Entry 6, Table 2.22). 

Warwel S, Sojka M, R6sch M (1993) Synthesis of Dicarboxylic Acids by Transition-Metal Catalyzed Oxidative Cleavage of Terminal-Unsaturated Fatty Acids. 164 79-98 Weinreb SM (1997) N-Sulfonyl Imines - Useful Synthons in Stereoselective Organic Synthesis. 190 131-184... 

In the N-sulfonyl imine-catalyzed sulfoxidation, aqueous hydrogen peroxide serves as the final oxidizing agent, which is clearly of practical advantage. In principle it can be assumed that either an oxaziridine (F, Scheme 10.17) or a hydroper-oxy hemiaminal (H, Scheme 10.17) can result as the active species from the reaction of the N-sulfonyl imine E with hydrogen peroxide (Scheme 10.17). For imine 79 the idea of an intermediate oxaziridine is supported by the experimental finding that oxidation by the isolated oxaziridine and in the catalytic reaction (using 79 and... 

Similar to the addition to HFIPA, the /MCD-mediated addition of methyl, phenyl, and naphthyl acrylates to N-sulfonyl imines afforded the (S)-adduct, which is opposite to that observed with aldehydes (Table 5.12) [95]. The best conditions were found using either dichloromethane or acetonitrile as solvent. 

As in catalytic ylide epoxidation (see Section 10.2.1.1), an alternative catalytic cycle can be based on generation of the ylide in situ by reaction of a sulfide with an alkyl halide to form a salt, which can then be deprotonated [76]. In 2001, Saito et al. reported the asymmetric version of this cycle using a 3 1 ratio of alkyl halide to sulfonyl imine (see Scheme 10.18) [81]. Good yields and ee-values were reported for aryl- and styryl-substituted aziridines using stoichiometric amounts of sulfide 24, and the diastereoselectivities ranged from 1 1 to 4 1. Unfortunately, when loadings were reduced the reaction times became longer and lower yields were reported (see Table 10.2). 

The cationic rhodium complexes such as [Rh(cod)(MeCN)2]BF4/dppb were the most efficient catalysts for addition of arylboronic acids or Ph4BNa to both aromatic and aliphatic A-sulfonyl imines.993 994 The asymmetric version giving optically active amines was achieved by amidomonophosphine catalysts (Equation (225)).995... 

Further studies concerning aza Diels-Alder reactions of N-sulfonyl imines have been carried out by Holmes et al. [200] and Whiting et al. [201,202], and the utility of glyoxylato imines for the synthesis of cyclic amino acids has been investigated by Stella s group [203, 204]. An extensive study concerning intramole-... 

In contrast to the hydrazones mentioned above, a,/ -unsaturated N -sulfonyl imines react as electron-deficient diene component in aza Diels-Alder reactions. In addition to several investigations dealing with their intermolecular cycloadditions under thermal and under high pressure conditions [231-234], Boger s... 

N-Sulfonyl Imines - Useful Synthons in Stereoselective Organic Synthesis... 

Biphasic basic oxidation using technical grade (50-60%) 3-chloroperbenzoic acid affords this oxaziridine in - 4 hr In a 2-L, three-necked, Morton-flask equipped with a mechanical stirrer was placed 22.6 g (0.083 mol) of crude (+)-[(7,7-dimethoxycamphoryl)sulfonyl]imine, 42.6 g (0.13 mol) of 3-chloroperoxybenzoic acid (50-60%) in 450 mL of methylene chloride, and 450 mL of saturated potassium carbonate solution. The reaction mixture was stirred vigorously until the oxidation was complete as indicated by TLC (Note 27) at which time 500 mL of water was added, the organic layer was separated and the aqueous layer was extracted with methylene chloride (2 x 500 mL). The combined organic extracts were washed with saturated sodium sulfite (300 mL) and water (300 mL), and dried over anhydrous magnesium sulfate. 

Oxidation of (+)-[(7,7-dimethoxycamphoryl)sulfonyl]imine (96%) and (+)-[(7,7-dichlorocamphoryl)sulfonyl]imine (98%)10 with 3-chloroperbenzoic acid has been reported. The procedure described here uses less hazardous and less expensive peracetic acid with the aid of Aliquat 336.10 However, this system requires 40 hr vs. 4 hr using 3-chloroperbenzoic acid for oxidation of (+)-[(7,7-dimethoxy-camphoryl)sulfonyl]imine to the oxaziridine. 

Dimethoxycampt,oryl)sulfonyl]imine 3H-3a,6-Methano-2,l-ben2isothiazole,... 

Furthermore, its Ir-complexes have performed successfully in the reductive coupling of alkynes with N-sulfonyl imines (08CAJ1384). The general synthetic route to SOLPHOS derivatives of type 59 is depicted in Scheme 13. 

In this chapter, we describe our effort to develop GGTIs with novel scaffolds [13,14]. Our approach commenced with the constrnction of a novel library of dihydropyrroles and tetrahydropyridines derived from the phosphine-catalyzed annulation of resin-bound allenoates and A-sulfonyl imines. Derivatization of one of the initial hits, dihydropyrrole-carboxyhc... 

The addition of arylboronic acids to imines in an aqueous solvent gave a mixture of amine (Eq. 6) and alcohol (Eq. 4) because the imines were partially hydrolyzed to the aldehyde during the reaction. The use of Ph4BNa in place of phenylboronic acid allowed the catalytic addition to various N-sulfonyl imines in the absence of water (Eq. 6). The representative results are summarized in Table 5. The cationic rhodium complexes such as [Rh(cod)(MeCN)2]BF4 was found to be the most efficient catalyst for both aromatic and aliphatic N-sulfonyl imines whereas no reactions were observed for N-alkyl and N-aryl imine derivatives. 

Recently, Sisko and Weinreb have developed a new, in situ procedure for effecting A -sulfonyl imine Diels-Alder reactions. The method consists of treating an aldehyde with an A -sulfinyl sulfon-amide/boron trifluoride etherate in the presence of a diene (Scheme 3). Under these conditions the IV-sul-finyl sulfonamide reacts with the aldehyde to produce an /V-sulfonyl imine. This reaction, developed by Kresze, has been used previously for preparing imines from simple, non-enolizable aldehydes (c/. 1,2), but had not been applied to more complex aldehydes. As can be seen from the scheme, the cycload-... 

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