Stereoselective synthesis of perillaldehyde-based chiral β-amino acid derivatives through conjugate addition of lithium amides

• Zsolt Szakonyi,
• Reijo Sillanpää and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2014, 10, 2738–2742, doi:10.3762/bjoc.10.289

• ][34]. From this aspect, chiral, monoterpene-based α,β-unsaturated esters might be excellent starting materials, in which the natural monoterpene skeleton may serve as the chiral origin for the stereoselective construction of the β-amino acid moiety. Our present aim was the synthesis of new, limonene

• 10D (see Scheme 2). Conclusion In conclusion, the highly stereoselective Michael addition of lithium dibenzylamide and (R)-N-benzyl-N-α-methylbenzylamide to tert-butyl perillate (3) proved to be an efficient method for the preparation of limonene-based β-amino acids through the three-step

Selective allylic hydroxylation of acyclic terpenoids by CYP154E1 from Thermobifida fusca YX

• Anna M. Bogazkaya,
• Clemens J. von Bühler,
• Sebastian Kriening,
• Alexandrine Busch,
• Alexander Seifert,
• Jürgen Pleiss,
• Sabine Laschat and
• Vlada B. Urlacher

Beilstein J. Org. Chem. 2014, 10, 1347–1353, doi:10.3762/bjoc.10.137

• point for engineering a highly selective CYP102A1 variant for terminal hydroxylation of (4R)-limonene at allylic C7 leading to perillyl alcohol. While the wild type did not hydroxylate (4R)-limonene at the C7 position, the triple mutant A264V/A238V/L437F converted (4R)-limonene to perillyl alcohol with

• made also during mutagenesis of CYP102A1 where high regioselectivity and high catalytic activity are not mutually exclusive properties. While for geranylacetone (9) the most selective mutant showed only 2% of the wild type activity, for limonene the most selective mutant had more than threefold wild

Garner’s aldehyde as a versatile intermediate in the synthesis of enantiopure natural products

• Mikko Passiniemi and
• Ari M.P. Koskinen

Beilstein J. Org. Chem. 2013, 9, 2641–2659, doi:10.3762/bjoc.9.300

• the same chemical structure, but differ from each other only by being mirror images (e.g., (R)(+)/(S)(−)-limonene and (S)(+)/(R)(–)-carvone, Figure 1). This sounds like an insignificant difference, but in reality enantiomers can have a totally different, even contradictory, effect on living organisms

• . As an example, (R)-limonene smells of oranges, whereas the (S)-enantiomer has a turpentine-like (with a lemon note) odor. The difference in physiological effects of enantiomers is of utmost importance especially for the pharmaceutical industry, but increasingly also in agrochemicals [2][3] and even

• , strategies to avoid this undesired reaction have been developed. However, despite these important achievements, much more research needs to be done to increase the scopes of these reactions, the overall efficiency, and environmental sustainability. Structures of limonene, carvone and thalidomide. Structure

Flow photochemistry: Old light through new windows

• Jonathan P. Knowles,
• Luke D. Elliott and
• Kevin I. Booker-Milburn

Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229

• , which is a significant improvement on the microreactor starting point [68]. Toluene has been employed as a photosensitiser in the addition of methanol to limonene (56, Scheme 18). The reaction was performed in a quartz microreactor; however, the reaction suffered from poor product selectivity and d.e

Stereoselective synthesis of trans-fused iridoid lactones and their identification in the parasitoid wasp Alloxysta victrix, Part II: Iridomyrmecins

• Robert Hilgraf,
• Nicole Zimmermann,
• Lutz Lehmann,
• Armin Tröger and
• Wittko Francke

Beilstein J. Org. Chem. 2012, 8, 1256–1264, doi:10.3762/bjoc.8.141

• , all eight stereoisomers of trans-fused iridomyrmecins were synthesized starting from the enantiomers of limonene. Combined gas chromatography and mass spectrometry including enantioselective gas chromatography revealed that volatiles released by the endohyperparasitoid wasp Alloxysta victrix contain

• Y and Z which, according to their mass spectra, were suggested to be trans-fused iridomyrmecins [3][4]. Since no synthetic reference compounds were available, all eight trans-fused iridomyrmecins had to be prepared. To complete the synthesis of this suite, we started from optically active limonene

• route may generally be used for the synthesis of all eight stereoisomers of trans-fused iridomyrmecins, it suffers from several major disadvantages such as high costs of (S)-pulegone and difficult separations of diastereomeric mixtures. Starting from the cheaply available pure enantiomers of limonene

Stereoselective synthesis of trans-fused iridoid lactones and their identification in the parasitoid wasp Alloxysta victrix, Part I: Dihydronepetalactones

• Nicole Zimmermann,
• Robert Hilgraf,
• Lutz Lehmann,
• Daniel Ibarra and
• Wittko Francke

Beilstein J. Org. Chem. 2012, 8, 1246–1255, doi:10.3762/bjoc.8.140

• Nicole Zimmermann Robert Hilgraf Lutz Lehmann Daniel Ibarra Wittko Francke Department of Chemistry - Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, D-20146 Hamburg, Germany 10.3762/bjoc.8.140 Abstract Starting from the enantiomers of limonene, all eight stereoisomers of

• trans-fused dihydronepetalactones were synthesized. Key compounds were pure stereoisomers of 1-acetoxymethyl-2-methyl-5-(2-hydroxy-1-methylethyl)-1-cyclopentene. The stereogenic center of limonene was retained at position 4a of the target compounds and used to stereoselectively control the introduction

• trans-fused dihydronepetalactones starting from pure, cheaply available enantiomers of limonene. Route to trans-fused dihydronepetalactones a and b starting from (S)-pulegone For comparison, the synthesis of a and b was carried out following Wolinsky’s approach: (S)-Pulegone (9) was transformed to trans