3010-03-5Relevant articles and documents
Photoredox-Catalyzed Cα-H Cyanation of Unactivated Secondary and Tertiary Aliphatic Amines: Late-Stage Functionalization and Mechanistic Studies
Yilmaz, Ozgur,Oderinde, Martins S.,Emmert, Marion H.
, p. 11089 - 11100 (2018/09/12)
This paper describes the development and mechanistic studies of a general, high-yielding amine Cα-H cyanation protocol via photoredox catalysis. Inexpensive NaCN is employed as the cyanide source and air is the external oxidant, resulting in mild and highly functional group tolerant conditions. Notably, efficient Cα-H cyanations of secondary and tertiary aliphatic amines and of complex, biologically active compounds (drugs) can be performed using the established methodology. Mechanistic studies suggest that the carboxylic acid additive has three effects: formation of a stabilizing hemiaminal intermediate, prevention of catalyst decomposition by protonating the substrate, and modulation of fluorescence quenching of the photoexcited catalyst species.
Organocatalytic Glycosylation by Using Electron-Deficient Pyridinium Salts
Das, Somnath,Pekel, Daniel,Neud?rfl, J?rg-M.,Berkessel, Albrecht
supporting information, p. 12479 - 12483 (2015/10/12)
A new organocatalytic glycosylation method based on electron-deficient pyridinium salts is reported. At ambient temperature and catalyst loadings as low as 1 mol %, 2-deoxyglycosides were formed from benzyl- and silyl-protected glycals and primary or secondary glycosyl acceptors, with excellent yields and anomeric selectivity. Mechanistic investigations point to alcohol-pyridinium conjugates (1,2-addition products) as key intermediates in the catalytic cycle.
POSITIVE RESIST COMPOSITION AND PATTERNING PROCESS
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, (2010/04/23)
A positive resist composition comprises (A) a resin component which becomes soluble in an alkaline developer under the action of an acid and (B) an acid generator. The resin (A) is a polymer comprising recurring units containing a non-leaving hydroxyl group represented by formula (1) wherein R1 is H, methyl or trifluoromethyl, X is a single bond or methylene, m is 1 or 2, and the hydroxyl group attaches to a secondary carbon atom. The composition is improved in resolution when processed by lithography.
