137625-68-4Relevant academic research and scientific papers
Dauben-Michno oxidative transposition of allylic cyanohydrins - Enantiomeric switch of (-)-carvone to (+)-carvone
Hudlicky, Jason R.,Werner, Lukas,Semak, Vladislav,Simionescu, Razvan,Hudlicky, Tomas
, p. 535 - 543 (2011/10/03)
Allylic cyanohydrins were subjected to Dauben-Michno oxidation at low temperatures to provide β-cyanoenones in good to excellent yields. The potential of this oxidative transposition as a means of an enantiomeric switch of enones containing a latent plane of symmetry was tested by conversion of (-)-carvone to its enantiomer.
S-(+)-Carvone as Starting Material in Synthesis (Part 4). Conjugate Addition of Cyanide and Grignard Nucleophiles Followed by Annulation to Functionalized Decalones.
Verstegen-Haaksma, Anja A.,Swarts, Henk J.,Jansen, Ben J. M.,Groot, Aede de
, p. 10073 - 10082 (2007/10/02)
Two conjugate addition/annulation methodologies for S-(+)-carvone are reported.The conjugate addition of Grignard reagents, followed by the Lewis acid catalyzed Michael reaction of the intermediate silyl enol ethers with MVK and cyclization of the diketon
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
Influence of a Hydroalcoholic Solvent on the Enantioselectivity of α-Amino nitrile Hydration Catalysed by Chiral Ketones
Lagriffoul, Pierre-Henri,Tadros, Ziad,Taillades, Jacques,Commeyras, Auguste
, p. 1279 - 1285 (2007/10/02)
The enantioselective hydration of α-aminonitriles 1, RCH(CN)NH2 i; 1c: R = Ph> has been achieved in an alkaline hydroalcoholic medium in the presence of chiral ketonic catalysts.Of the different ketones used, (-)-(5R,3R,2R)-5-(methylethenyl)-3-cyano-2-methylcyclohexanone (8) gives rise to significant enantioselectivity D/kL = 2.1; T = 10 deg C; solvent, water-propan-2-ol (45:55,v/v)>.Although the structure of the catalyst could probably be improved, we show in this paper that the efficiency and especiallythe enantioselectivity of the catalyst are not only under steric control but also depend on the nature and composition of the hydroalcoholic solvent.Thus, for the three aminonitriles studied in the presence of the catalyst 8, the increase in percentage of propan-2-ol favours the hydration of the D α-aminonitrile as shown for the hydration of 1c for which the ratio kD/kL increases threefold when the percentage of propan-2-ol increases from 10 to 95percent.
