A -sulfonyl imine

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). 

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... 

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... 

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-... 

One synthetic problem in aza Diels-Alder reactions is the stability of imines under the influence of Lewis acids. It is desirable that the Lewis acid-activated imines are immediately trapped by dienes or dienophiles. In 1989, Sisko and Weinreb reported a convenient procedure for the aza Diels-Alder reaction of an aldehyde, a 1,3-diene, and A-sulfinyl p-toluenesulfonamide via A -sulfonyl imine produced in situ—a stoichiometric amount of BF3 OEt2 was used as a promoter [28a]. 

Direct attack on oxygen was postulated in the reaction of Grignard and lithium reagents with [E]-2-benzenesulfonyl-3-phenyloxaziridine 55. The principal organic products were alcohols and phenols (50-95% yields), derived from the organometallic reagent, and amines derived from addition of the organometallic to the intermediate A -sulfonyl imine (60-95%). 

A number of examples of inter- and intramolecular additions of ailyl silanes to N-sulfonyl imines have been reported. Weinreb and coworkers have combined the Kresze methodology for forming A-sulfonyl imines and subsequent additi-... 

As an efficient catalyst for enantioselective aza-MBH reaction, bifunctional phosphine catalyst CP17 has also been immobilized on a series of den-drimers. The dendrimer-immobilized catalyst CP44 was more effective than catalyst CP17 for the aza-MBH reaction of A-sulfonyl imines with MVK, EVK or acrolein. The catalyst could be separated easily from the reaction mixture by simple filtration after the reaction and reused without obvious loss of activity (Scheme 2.233). ... 

Bode, et al. developed a highly enantioselective azadiene Diels-Alder reactions catalyzed by chiral A-heterocyclic carbenes. Scheme 3.28 [43]. Reactions of alkyl fra -4-oxo-2-butenoate 80 with A-sulfonyl imines 81 and catalyst 82 (10-15 mol%), DIPEA (10 mol%) in toluene-THF (10 1) at room temperature afforded the dihydopyridinones 83 in excellent diastereo- and enantioselectivity (>50 1 cw-diastereoselectivity, 99% ee). The LUMO -controUed inverse electron demand Diels-Alder cycloaddition was facilitated by NHC-carbene catalyst 82. Similar reactions without the catalyst would require high pressure (12 bar) or high temperature. The high cw-diastereoselectivity which would arise from (Z)-enolate reacting with the dienophile is rationalized as depicted in Scheme 3.28. 

It has also been found that the asymmetric alkylation of indoles with A-sulfonyl imines may be catalysed by a binaphthyl-based chiral sulfonimide. " ... 

An unprecedented protocol for the stereoselective synthesis of stracturally diverse electron-deflcient alkenes in moderate to excellent yields from readily accessible A-sulfonyl imines and stabilized phosphonium ylides has been reported. The oleflna-tion reaction of (V-sulfonyl imines with nitrile-stabilized phosphonium ylides affords an array of a./S-unsaturated nitriles with high Z selectivity, and the reactions with ester-, amide-, and ketone-stabilized phosphonium ylides afford a,)3-unsaturated esters, amides, and ketones with high E selectivity, respectively (Scheme 3). 

Cycloaddition Reactions. Dichloroketene, A-sulfonyl-imines, diazomethane, and aroylketenes add to (1) to provide good yields of a cyclobutenone, 2-azetines, a pyrazole, and 4-pyrones, respectively. Cooligomerization of three molecules of (1) with one molecule of carbon dioxide proceeds in the presence of Ni catalyst, giving a 2-p5Tone derivative in 90% yield. ... 

The reaction of tropone 107 or 2,7-diphenyltropone with arenesulfonyl isocyanates gives A-sulfonyl imines 108, which react with excess isocyanate to give the bicyclic adducts 109149 ... 

Chiral Lewis acids derived from complexes between copper(I) chloride with phosphino sulfenyl ferrocenes are efficient catalysts for enantioselective aza-Diels-Alder reaction of A-sulfonyl imines with Danishefsky-type dienes (eq 47), and asymmetric conjugate addition of Grignard reagents to cyclic enones (eq 48).136... 

LDA has been identified as the base of choice for the olefination of A-sulfonyl imines with semistabilized triphenylphosphonium ylides [221], A range of A-(p-toluenesulfonyl) aromatic imines undergo olefination with benzylidenetriphenylphosphoranes to give Z-stilbene derivatives with greater than 99 1 stereoselectivity (Scheme 51). The exclusive Z selective olefination reaction... 

A further application of cyclopentadienyl rhodium is in the regioselective coupling of benzamides with aromatic A-sulfonyl imines to yield branched amine products " such as (58). There has also been a report of X-ray crystallographic and DFT studies that are relevant to the ortho-cupration of aromatic amides by amidocuprates before their functionalization with electrophiles. " ... 

The A -SES group can be incorporated by treating an aldehyde with (V-sulfinyl-p-trimethylsilylethanesulfonamide (SESNSO) (13), which can be made by treating the sulfonamide (12) with Thionyl Chloride and a catalytic amount of N,N-dichloro-p-toluenesulfonamide (eq 7) (see also N-Sulfinyl-p-toluenesulfonamide). The )V-sulfonyl imine can be used in situ in a number of reactions. For example, the A(-sulfonyl imine from aldehyde (14) reacts with 2,3-dimethylbutadiene (eq 8) to give the Diels-Alder adduct (15). Treatment of (15) with fluoride ion affords the bicyclic lactam (16). Also, the IV-sulfonyl imine derived from isobutyraldehyde and (13) reacts with Vinylmagne-sium Bromide to provide the allylic SES-sulfonamide (17) in 65% yield (eq 9). ... 

Garcia Mancheno O, Gomez Arrayas R, Carretero J-C (2004) Chiral copper complexes of phosphino sulfenyl ferrocenes as efflcient catalysts for enantioselective formal Aza Diels-Alder reactions of A-sulfonyl imines. J Am Chem Soc 126 456-457... 

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