| The Strecker reaction which was reported already in 1850 is the oldest knownsynthesis ofα-amino acids. This reaction comprises a condensation of an aldehyde,ammonia, and cyanide source, followed by subsequent hydrolysis of the resultingα-amino nitrile. In addition, the Strecker reaction represents one of the simplest andmost economical methods for the preparation ofα-amino acids on lab scale as wellon a technical scale. Furthermore, the substrates are very cheap and available incommercial quantities. In industry, the Strecker reaction is applied widely due tothose economically favorable properties,α,α-dialkylated amino acids (α,α-DAAs)have attracted the attention of the pharmaceutical industry. Their incorporation intopeptides and proteins might affect the secondary or tertiary structure and conferunusual and interesting biological properties. The quaternary center in anα,α-DAApreserves its stereochemical integrity and often imparts increased metabolic stabilityto the peptide. Also, manyα,α-DAAs are powerful enzyme inhibitors. Efforts haverecently culminated in efficient catalysts for the cyanation of aldimines affordinga-amino acids of high enantiomeric purity. In principle, the same strategy could beapplied to ketoimines to affordα,α-DAAs. In practice, the enantiotopic faces ofketoimines are not as easily discriminated as those of aldimines. To the best of ourknowledge, there are only three research groups have reported their works on thissubject. In this dissertation, catalytic asymmetric silylcyanation of ketoimine wasstudied, and several original achievement have been made.Firstly, a series of different kind of ketoimines were prepared using simple method. Among these ketoimines, we have found N-tosyl ketoimines had their owncomparative advantages, so they were chosen for study of catalytic silylcyanation.An effective, facile and low cost approach to racemic adduct of Strecker reaction hasbeen established where a certain of strong organic base (such as Et3N and TMG) orsome simple N-oxide (like trimethylamine oxide and triethylamine oxide) has beenfound to be excellent catalyst (＞95％isolated yield).A large library of chiral guanidines, chiral amines, chiral diamines, chiralN-oxide and N,N-dioxide were build up thereafter. In the catalyst screening, wefound that chiral guanidines had fantastic catalytic reactivity with bad asymmetricinductivity (＜17％ee); chiral amines showed inferior catalytic reactivity with lowasymmetric inductivity (＜38％ee); chiral diamines displayed high catalyticreactivity with very low asymmetric inductivity (＜26％ee); chiral N-oxideexhibited moderate catalytic reactivity with bad asymmetric inductivity; chiralN,N-dioxides generally possessed comparatively high catalytic reactivity, amongthem a L-proline derived bicyclo N,N'-dioxide C19a was found to be a superiorcatalyst with good asymmetric inductivity (70％ee, 0℃).Then additive effect has been investigated. Experimental data showed thathydroxyl groups were essential to accelerating the reaction where DAHQ wasproved to be the best additive at present (5％mol cat., 20％mol DAHQ, 85％ee, -20℃). Moreover, this catalytic system is moisture-tolerant and air-tolerant. Under theoptimized condition, substrate scope was surveyed with good results (90～99％isolated yield, 32～91％ee).Finally, mechanism study and discussion were stated in the text. With supportof proper experimental phenomena, a rational catalytic cycle was proposed and apossible hydrogen bond involved hyper valent silicic octahedron transition state waspropounded for successful explanation of the origin of chiral induction where an S-product was generated.
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