528-24-5Relevant academic research and scientific papers
Stereoselective synthesis of trans-fused iridoid lactones and their identification in the parasitoid wasp Alloxysta victrix, Part I: Dihydronepetalactones
Zimmermann, Nicole,Hilgraf, Robert,Lehmann, Lutz,Ibarra, Daniel,Francke, Wittko
, p. 1246 - 1255 (2012/10/08)
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 of the other chiral centers during the synthesis. Basically, this approach could also be used for the synthesis of enantiomerically pure trans-fused iridomyrmecins. Using synthetic reference samples, the combination of enantioselective gas chromatography and mass spectrometry revealed that volatiles released by the endohyperparasitoid wasp Alloxysta victrix contain the enantiomerically pure trans-fused (4R,4aR,7R,7aS)-dihydronepetalactone as a minor component, showing an unusual (R)-configured stereogenic center at position 7.
Terpenes and Terpene Derivatives, XXIX Synthesis and Olfactive Properties of (-)- and rac-Silphiperfol-5-en-3-ol and of Some Tris-nor Derivatives
Weyerstahl, Peter,Brendel, Joachim
, p. 669 - 678 (2007/10/02)
The new sesquiterpene alcohols silphiperfol-5-en-3-ol and the corresponding 7-epi compound (+)-1b, important constituents of the essential oil of Artemisia laciniata have been synthesized in 13 steps by starting from (R)-(+)-pulegone (6) in an overall yield of 8percent.The key reaction is the copper-catalyzed 1,4-Grignard addition of the iodo acetal 34 to the enone (+)-4 in the presence of TMSCl and TMEDA to give the silyl ether 38.Hydrolysis with spontaneous aldol cyclization and dehydration leads to the silphiperfolenones (+)-2a,b which are separable by flash chromatgraphy.The reduction with L-selectrideR gives the alcohols (-)-1a and (+)-1b which are identical in all physical properties with the isolated natural compound.With LiAlH4 the diastereoisomers 42a,b are formed.Olfactive evaluation of the isomers (-)-1a and (+)-1b has shown that the odor of the naturally occuring mixture of 1a,b with the descriptors woody, ambergris, slightly camphoraceous is correctly assigned. (-)-1a represents the more woody and camphoraceous, (+)-1b the more animal facette of ambergris.The odor of rac-1a,b, of the diasteroisomers 42a,b and of the ketones (+)-2a,b is also described as well as that of the tris-nor-silphiperfolene derivatives 29-31. Key Words: Artemisia laciniata / Sesquiterpene alcohols, tricyclic / Structure-odor correlation / (R)-(+)-Pulegone / 1,4-Grignard reaction
An efficient synthesis of the Prelog-Djerassi lactone methyl ester from (-)-trans-pulegenic acid
Hacini, Salih,Santelli, Maurice
, p. 7787 - 7792 (2007/10/02)
The (+)-Prelog-Djerassi lactone methyl ester 1 was obtained from trans-pulegenic acid 2 in seven steps in 22 % overall yield; three more steps from an unwanted diastereoisomer gave additionnal 5%.
