84194-66-1Relevant articles and documents
Expanding substrate scope of lipase-catalyzed transesterification by the utilization of liquid carbon dioxide
Hoang, Hai Nam,Matsuda, Tomoko
, p. 7229 - 7234 (2016/10/26)
Secondary alcohols having bulky substituents on both sides of the chiral center are often poor substrates for most lipases. Here we reported that substrate scopes of two of the most used lipases, Candida antarctica lipase B and Burkholderia cepacia lipase, were found to be expanded toward more bulky secondary alcohols such as 1-phenyl-1-dodecanol and 2-methyl-1-phenyl-1-propanol by simply using them in liquid carbon dioxide as a solvent. The effects of solvents, reaction pressure, and pre-treatment of the enzyme with liquid CO2on this acceleration phenomenon were also studied.
Nonenzymatic dynamic kinetic resolution of secondary alcohols via enantioselective acylation: Synthetic and mechanistic studies
Lee, Sarah Yunmi,Murphy, Jaclyn M.,Ukai, Atsushi,Fu, Gregory C.
supporting information, p. 15149 - 15153 (2012/10/30)
Because of the ubiquity of the secondary carbinol subunit, the development of new methods for its enantioselective synthesis remains an important ongoing challenge. In this report, we describe the first nonenzymatic method for the dynamic kinetic resolution (DKR) of secondary alcohols (specifically, aryl alkyl carbinols) through enantioselective acylation, and we substantially expand the scope of this approach, vis-a-vis enzymatic reactions. Simply combining an effective process for the kinetic resolution of alcohols with an active catalyst for the racemization of alcohols did not lead to DKR, due to the incompatibility of the ruthenium-based racemization catalyst with the acylating agent (Ac2O) used in the kinetic resolution. A mechanistic investigation revealed that the ruthenium catalyst is deactivated through the formation of a stable ruthenium-acetate complex; this deleterious pathway was circumvented through the appropriate choice of acylating agent (an acyl carbonate). Mechanistic studies of this new process point to reversible N-acylation of the nucleophilic catalyst, acyl transfer from the catalyst to the alcohol as the rate-determining step, and carbonate anion serving as the Bronsted base in that acyl-transfer step.
2,3-Dihydroimidazo[1,2-a]pyridines: A new class of enantioselective acyl transfer catalysts and their use in kinetic resolution of alcohols
Birman, Vladimir B.,Uffman, Eric W.,Jiang, Hui,Li, Ximin,Kilbane, Corey J.
, p. 12226 - 12227 (2007/10/03)
The long-known, but previously unexplored 2,3-dihydroimidazo[1,2-a]pyridine (DHIP) has been shown to be a competent acyl transfer catalyst. Its chiral 2-phenyl derivatives obtainable in two steps from commercially available starting materials have proved to be effective acylation catalysts, giving high levels of enantioselectivity (s = 20-85) in kinetic resolution of secondary benzylic alcohols. A transition state model explaining the observed selectivity has been proposed. Copyright
