155486-41-2Relevant academic research and scientific papers
Auxiliary chiral ketones in the asymmetric synthesis of α-amino acids by Strecker reaction
Bousquet, C.,Tadros, Z.,Tonnel, J.,Mion, J.,Taillades, J.
, p. 513 - 520 (2007/10/02)
The asymmetric synthesis of α-aminoamides 1 R1CH(CONH2)NH2 1 = Ph-CH2, 1b: R1 = Pri, 1c: R1 = Ph> that leads to the corresponding α-amino acids is achieved by a classical Strecker reaction 1CHO, HCN, NH3> using an auxiliary chiral ketone (R2R'2CO) as a catalyst.In the presence of an aqueous solution of HCN and NH3, the (-)-5R-(methylethenyl)-3R-cyano-2R-methylcyclohexanone 2(-) leads to the 5R-(methylethenyl)-3R-cyano-2R-methyl-1R-cyano-cyclohexylamine 3 with 80percent stereoselectivity.Following condensation with R1CHO, this α-aminonitrile R2R'2C(CN)NH2 3 yields the corresponding iminonitrile which undergoes a second asymmetric addition of HCN yielding an asymmetric α-aminodinitrile 4 R2R'2C(CN)-NH-CHR1(CN) with stereoselectivity that varies betweeen 62percent (R1 = Ph) and 79percent (R1 = Ph-CH2).The α-aminodinitrile obtained as the major product undergoes regioselective hydration of the secondary aminonitrile moiety followed by the decomposition ("retro-Strecker") of the tertiary aminonitrile moiety yielding an optically active α-aminoamide (eg 78percent optical purity for 1a) and the auxiliary chiral ketone 2 and ketonic derivatives.Keywords - α-aminonitrile / α-amino acid / asymmetric synthesis
