Ti-Catalyzed Regio- and Enantioselective Synthesis of Unsaturated α-Amino Nitriles, Amides, and Acids. Catalyst Identification through Screening of Parallel Libraries

Structural Features of Titanium Complexes of Salicylaldiminato Derivatives of Amino Acids

“…For this characterization we used the hydrocyanation reaction of 6 to yield 7 (see Scheme 4), a system that was described previously by Hoveyda et al [5,13] The complexes 4b-d were employed. They all were more active than the in situ catalyst, generated by treatment of 3b with Ti(OiPr) 4 .…”

“…1 H NMR (300.1 MHz, CD 2 Cl 2 , 298 K): δ = 13.06 (s, 1 H, OH), 8.40 (s,1 H,CH=N),7 H,H phenyl ),2 H,H phenyl ),5.20 (s,1 H,3.75 (s,3 H,OCH 3 ) ppm. 13 C{ 1 H} NMR (75.5 MHz, CD 2 Cl 2 , 298 K): δ = 171.1 (C-1), 167.4 (CH=N), 137.7,133.3,132.4,129.3,128.8,128.2,119.6,117.3 (C phenyl 2344,1736,1625,1573,1493,1455,1429,1409,1338,1368,1331,1305,1276,1196,1173,1137,1115,1060,1032,1020,977,880,847,762,736,675,663,601,549 Sal*PhgOMe (3c): Triethylamine (173 mg, 1.70 mmol, 1.00 equiv.) was added to a solution of HCl·H-Phg-OMe (344 mg, 1.70 mmol, 1.00 equiv.)…”

“…After stirring at room temperature for 10 min, imine 6 (0.43 mmol) [13] was added and the mixture was cooled to 4°C. After an equilibration time of 20 min, trimethylsilyl cyanide (0.85 mmol) was added and a solution of nbutanol (0.64 mmol) in toluene (2 mL) was added through a syringe pump over a period of 10 h. After further stirring at 4°C for 14 h, the reaction was quenched by the addition of diethyl ether (5 mL).…”

Asymmetric Synthesis of Cyanohydrins

“…Snapper and Hoveyda have developed dipeptide ligands with solid-phase synthetic technology, and applied them to the asymmetric addition of TMSCN to imines (Strecker reaction) and ketones [157][158][159][160]. It was found that the 65-Al(OiPr) 3 complex was effective in catalyzing the enantioselective cyanosilylation of a wide range of aromatic and aliphatic ketones.…”

Efficient Solid‐Phase Synthesis of Peptide‐Based Phosphine Ligands: Towards Combinatorial Libraries of Selective Transition Metal Catalysts

“…Peptides have been applied for asymmetric azidation and for regioselective functionalisation of carbohydrates by Miller and co-workers. [3,4] Functionalised peptides complexing transition metals, have been utilised for a number of asymmetric addition and substitution reactions in the group of Hoveyda, [5][6][7][8][9][10][11][12] and peptidic catalysts for the Strecker reaction have been developed by Jacobsen and co-workers. [13][14][15] However, because of the expected high chemo-, regioand stereoselectivity of peptide-based catalysts, there is a need for the development of a method for the identification of the most efficient catalyst for any specific reaction.…”