Catalytic asymmetric cyanation

Spino, C. Recent developments in the catalytic asymmetric cyanation of ketimines. Angew. Chem., Int. Ed. Engl. 2004, 43, 1764-1766. 

The catalytic asymmetric cyanation of imines-the Strecker reaction-represents one of the most direct and viable methods for the asymmetric synthesis of a-amino... 

Catalytic asymmetric cyanation using 20 mol % of the complex of Ti(Oz-Pr)4 with diisoporpyl tartrate (10 Fig. 1) was reported by Oguni [42,43]. The mixture of Ti(Oi-Pr)4 and 10 (Fig. l)did not exhibit high enantioselectivity. Moreover, the selectivity and the reactivity were still low when the formed isopropyl alcho-hol was removed under reduced pressure using the freeze-dry method. High reactivity and an enantioselectivity of up to 90% were observed when the isopropyl alcohol was again added to the freeze-dried titanium complex. 

Recent developments in the catalytic asymmetric cyanation of ketimines. (c) T. Vilaivan, W. Bhanthumnauin, Y. Sritana-Anant, Curr. Org. Chem. 2005, 9, 1315-1392. Recent advances in catalytic asymmetric addition to imines and related C=N systems, (d) S. J. Connon, Angew. Chem. Int. Ed. 2008,47,1176-1178. The catalytic asymmetric Strecker reaction ketimines continue to join the fold. 

Catalytic Asymmetric Cyanation with Trimethylsilyl Cyanide as the Cyanide Source... 

Johnson s group developed a catalytic asymmetric cyanation/1,2-Brook rearrangement/C-acylation of acylsilanes with cyanoformates (Scheme 19.14). In the presence of (i ,/ )-(salen)Al 19, the corresponding cyanohydrin trimethylsilyl ethers of a-keto esters were obtained in moderate to good enantioselectivities (61-82% enantiomeric excess). Access to chiral (silyloxy)nitrile anions is facilitated by metal cyanide-promoted Brook rearrangement reaction of acylsilanes. 

Optically active cyanohydrins can be easily transformed to P-hydroxy amines, a-hydroxy and a-amino carboxylic acids, which represent versatile intermediates for the synthesis of biologically important compounds, including insecticides and medicines [189, 190]. Asymmetric cyanation of carbonyl compounds catalyzed by chiral metal complexes, particularly titanium compounds, has provided one of the most convenient protocols to the access of these type of compounds. The first example of catalytic asymmetric cyanation of aliphatic aldehydes was realized in Reetz s group using BINOL-Ti complex as the catalyst to give the cyanohydrins in up to 82% ee [104] (Scheme 14.85). 

Table 18 Catalytic asymmetric cyanation reactions of p,p-disubstituted a,p-imsaturated ketones using a chiral strontium catalyst...

Kurono N, Ohkuma T (2016) Catalytic asymmetric cyanation reactions. ACS Catal 6... 

Catalytic Asymmetric Cyanation with (R]-BINOLi/-PrOLi (10mol%) [87]... 

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