24150-22-9Relevant academic research and scientific papers
Cu(I)-catalyzed decarboxylative aldol-type and Mannich-type reactions for asymmetric construction of contiguous trisubstituted and quaternary stereocenters
Yin, Liang,Kanai, Motomu,Shibasaki, Masakatsu
scheme or table, p. 3497 - 3506 (2012/06/15)
The catalytic asymmetric decarboxylative aldol-type reaction between aldehydes and cyanocarboxylic acids and Mannich-type reaction between aldimines and cyanocarboxylic acids were developed. α,α,β-Trisubstituted- β-hydroxy nitriles bearing contiguous all-carbon quaternary and trisubstituted stereocenters were produced with moderate enantio- and diastereoselectivity in the presence of 10 mol % CuOAc-TANIAPHOS (or DTBM-SEGPHOS) complex in the aldol-type reaction. α,α,β- Trisubstituted-β-amino nitriles containing contiguous all-carbon quaternary and trisubstituted stereocenters were produced with moderate to high enantio- and diastereoselectivity using 5 mol % CuOAc-(R)-DTBM-SEGPHOS complex in the Mannich-type reaction. These reactions proceed through Cu(I)-catalyzed decarboxylative nucleophile generation, followed by the addition of the resulting chiral Cu-ketenimide to aldehydes or imines. Because the reactions proceed under very mild conditions at nearly neutral pH, the reactions are applicable to a wide range of substrate combinations, including both aromatic and aliphatic substrates. Finally, α,α,β-trisubstituted-β- amino nitriles were converted to β2,2,3-amino acid derivatives through simple acidic hydrolysis without any racemization and epimerization.
The synthesis and stereospecific solid-state photodecarbonylation of hexasubstituted meso- and d,l-ketones
Shiraki, Saori,Natarajan, Arunkumar,Garcia-Garibay, Miguel A.
scheme or table, p. 1480 - 1487 (2012/06/01)
Tertiary carbanions were trapped with half an equivalent of diphosgene to give meso- and d,l-hexasubstituted ketones in moderate yields and modest diastereoselectivities. The ketones were also synthesized by a step-wise synthesis in which the carbonyl group was first installed as an acid before activation and the second nucleophilic attack. This second method gave lower yields but similar diastereoselectivites. Steric limits of both methods were also determined. The photolysis of the resulting crystalline ketones gave a mixture of products in solution, but took place chemoselectively and diastereospecifically in the solid-state. The Royal Society of Chemistry and Owner Societies.
