464-43-7Relevant articles and documents
Simple Plug-In Synthetic Step for the Synthesis of (?)-Camphor from Renewable Starting Materials
Calderini, Elia,Drienovská, Ivana,Myrtollari, Kamela,Pressnig, Michaela,Sieber, Volker,Schwab, Helmut,Hofer, Michael,Kourist, Robert
, p. 2951 - 2956 (2021/06/18)
Racemic camphor and isoborneol are readily available as industrial side products, whereas (1R)-camphor is available from natural sources. Optically pure (1S)-camphor, however, is much more difficult to obtain. The synthesis of racemic camphor from α-pinene proceeds via an intermediary racemic isobornyl ester, which is then hydrolyzed and oxidized to give camphor. We reasoned that enantioselective hydrolysis of isobornyl esters would give facile access to optically pure isoborneol and camphor isomers, respectively. While screening of a set of commercial lipases and esterases in the kinetic resolution of racemic monoterpenols did not lead to the identification of any enantioselective enzymes, the cephalosporin Esterase B from Burkholderia gladioli (EstB) and Esterase C (EstC) from Rhodococcus rhodochrous showed outstanding enantioselectivity (E>100) towards the butyryl esters of isoborneol, borneol and fenchol. The enantioselectivity was higher with increasing chain length of the acyl moiety of the substrate. The kinetic resolution of isobornyl butyrate can be easily integrated into the production of camphor from α-pinene and thus allows the facile synthesis of optically pure monoterpenols from a renewable side-product.
Molecular cloning and functional characterization of a two highly stereoselective borneol dehydrogenases from Salvia officinalis L
Drienovská, Ivana,Kolanovi?, Dajana,Chánique, Andrea,Sieber, Volker,Hofer, Michael,Kourist, Robert
, (2020/01/11)
Enzymes for selective terpene functionalization are of particular importance for industrial applications. Pure enantiomers of borneol and isoborneol are fragrant constituents of several essential oils and find frequent application in cosmetics and therapy. Racemic borneol can be easily obtained from racemic camphor, which in turn is readily available from industrial side-streams. Enantioselective biocatalysts for the selective conversion of borneol and isoborneol stereoisomers would be therefore highly desirable for their catalytic separation under mild reaction conditions. Although several borneol dehydrogenases from plants and bacteria have been reported, none show sufficient stereoselectivity. Despite Croteau et al. describing sage leaves to specifically oxidize one borneol enantiomer in the late 70s, no specific enzymes have been characterized. We expected that one or several alcohol dehydrogenases encoded in the recently elucidated genome of Salvia officinalis L. would, therefore, be stereoselective. This study thus reports the recombinant expression in E. coli and characterization of two enantiospecific enzymes from the Salvia officinalis L. genome, SoBDH1 and SoBDH2, and their comparison to other known ADHs. Both enzymes produce preferentially (+)-camphor from racemic borneol, but (?)-camphor from racemic isoborneol.
Direct Reductive Amination of Camphor Using Iron Pentacarbonyl as Stoichiometric Reducing Agent: Features and Limitations
Afanasyev, Oleg I.,Amangeldyev, Artem,Chusov, Denis,Fatkulin, Artemy R.,Semenov, Sergey E.,Smirnov, Ivan,Solyev, Pavel N.
supporting information, p. 6289 - 6294 (2020/10/06)
The method of direct reductive amination of camphor and fenchone was proposed. The most effective reducing agent is iron carbonyl. No ligands or solvents are needed. The stereochemistry of the corresponding products was determined by HMBC, HSQC, and NOESY
