By Tsubasa Inokuma
This paintings describes novel, powerful hydrogen-bond (HB) donor catalysts in response to a recognized bifunctional tertiary amine-thiourea, a privileged constitution, which has been confirmed to be the most commonplace organocatalysts. those HB donor catalysts derived from quinazoline and benzothiadiazine have been in the beginning synthesized as novel HB donors with their HB-donating skills being measured by way of analytical tools. They have been came across to be powerful for numerous uneven differences together with Michael reactions of a, b-unsaturated imides and hydrazination reactions of 1,3-dicarbonyl compounds. Thiourea catalysts that experience an extra sensible crew also are defined. particularly, thioureas that undergo a hydroxyl staff have been synthesized and for this reason used as novel bifunctional organocatalysts for catalytic, uneven Petasis-type reactions concerning organoboronic acids as nucleophiles. those addition reactions have been tough to accomplish utilizing current organocatalysts. one of many constructed catalytic tools will be utilized to the synthesis of biologically fascinating peptide-derived compounds owning unnatural vinyl glycine moieties. those findings introduce new standards required for the advance of organocatalysts for uneven reactions, therefore creating a major contribution to the sphere of organocatalysis.
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90, CHCl3, 80 % ee). 0096 mmol) at room temperature. After 3 h, the reaction mixture was concentrated in vacuo, and the residue was purified by column chromatography (hexane/EtOAc = 2/1) to afford desired product 13 (23 mg, 96 %). 24, CHCl3). 0015 mmol) at room temperature. 1 mg, 64 %). 21, CHCl3). 1 Introduction and Background The hydrazination of 1,3-dicarbonyl compounds with azodicarboxylates is a valuable method for installing an amino group. When 2-monosubstituted 1,3dicarbonyl compounds are used as nucleophiles, the resulting products possess a-amino acid moieties bearing quaternary stereogenic centers.
With quinazoline catalyst 5b, even sterically less-hindered methyl ester 16b could be used and the desired aminated compound 17b was produced in 94 % yield and 91 % ee (entry 1).
16. 16. 7; IR (KBr) m 3123, 1678 cm-1; MS (FAB+) 262 (M ? H+, 100); Anal. Calcd. 35. 3; IR (CHCl3) m 3330, 3017, 1739, 1670, 1479 cm-1; MS (FAB+) 220 (M ? H+, 100); HRMS (FAB+) Calcd. 0967. 5; IR (CHCl3) m 3331, 2933, 1699, 1673, 1600, 1479, 1347 cm-1; MS (FAB+) 406 (M ? H+, 54), 135 (100); HRMS (FAB+) Calcd. 2421. 8; IR (CHCl3) m 3314, 2360, 1710, 1683, 1604, 1514, 1478, 1243 cm-1; MS (FAB+) 366 (M ? H+, 92), 135 (100); HRMS (FAB+) Calcd. 00, CHCl3, 92 % ee). 1; IR (CHCl3) m 3316, 3024, 1709, 1683, 1514, 1479, 1217 cm-1; MS (FAB+) 378 (M ?