Cyanides, arylsulfonyl

Mass spectral data on l-(arylsulfonyl)-l//-azepines have been amassed,73 and the fragmentation patterns of several 1-acyl-1//-azepines elucidated.61 For the latter systems, the base peaks correspond to the azatropylium cation (m/z 92). Loss of hydrogen cyanide to yield the cyclo-pentadienyl cation (m/z 65) has also been noted. 

This phase-transfer-catalyzed asymmetric Strecker reaction is further elaborated by the use of a-amido sulfone as a precursor of N-arylsulfonyl imine. In this system, the reaction can be conducted with a slight excess of potassium cyanide (1.05 equiv.), and the reaction leads to completion within 2h (Table 5.15) [46b],... 

Isoquinoline, potassium cyanide, and an alkyl- or arylsulfonyl chloride reacted to yield 2-arylsulfonyl- an 2-alkyIsulfonyl-l,2-dihydroisoquinaldonitriles (62). As is the case with Reissert compounds these analogs do not exhibit any nitrile absorption in the... 

There is only sparse literature on [4 + 2] cycloadditions of nitriles with 1,3-dienes. In general, simple alkyl and aryl nitriles will only react at high temperatures and under these conditions the product dihy-dropyridines usually disproportionate.However, certain types of electron-deficient nitriles appear to be reactive dienophiles under milder conditions. For example, arylsulfonyl cyanides cycloadd to 1,3-dienes to afford adducts as shown in Scheme 1This methodology has not teen widely explored and little is known about the regiochemistry of the process. 

Tetrazoles are usually prepared by the reaction of an azide with a nitrile, or an activated amide tri-n-bntyltin azide and trimethylsilyl azide are more convenient and safer reagents than azide anion in some cases copper(I) oxide catalysis in the trimethylsilyl azide protocol is very efficient for the prodnction of A-unsubstituted tetrazoles, " and arylsulfonyl cyanides react with organic azides very efficiently giving rise to 1-substitnted 5-arylsulfonyl-tetrazoles. Zinc bromide can be used to catalyse the reaction between sodinm azide and nitriles in hot water. Intramolecnlar examples involving cyanamides proceed in hot DMF. 3 In additions to nitriles, one can inclnde triethylammoninm chloride (instead of ammoninm chloride)... 

It was found that intramolecular hydrogen bonding facilitates nucleophilic addition of sulfones to MBH adducts in a single step to acquire the substituted allyl sulfones in poly(ethylene glycol) (PEG) as the solvent at high temperatures. However, Reddy et have developed a general and practical synthesis of substituted allyl sulfones in both high yields and selectivity by the reaction of a MBH adduct with arylsulfonyl cyanide (Scheme 3.149). 

Asymmetric phase-transfer catalytic addition of cyanide to C=N, C=0, and C=C bonds has been recently explored, which has been demonstrated to be an efficient method toward the synthesis of a series of substituted chiral nitriles. In this context, Maraoka and coworkers disclosed an enantioselective Strecker reaction of aldimines by using aqueous KCN [140]. In this system, the chiral quaternary ammonium salts (R)-36e bearing a tetranaphthyl backbone were found to be remarkably efficient catalysts (Scheme 12.25). Subsequently, this phase-transfer-catalyzed asymmetric Strecker reaction was further elaborated by use of a-amidosulfones as precursor of N-arylsulfonyl imines. Interestingly, the reaction could be conducted with a slight excess of potassium cyanide [141] or acetone cyanohydrin [40] as cyanide source, and good to high enantioselectivities were observed. In contrast, the asymmetric phase-transfer-catalytic cyanation of aldehydes led to the cyanation products with only moderate enantioselectivity [142]. 

---