25946-29-6Relevant academic research and scientific papers
Identification of m-Mentha-3(8),6-diene (isosylveterpinolene) in black pepper oil
Nussbaumer, Cornelius,Cadalbert, Riccardo,Kraft, Philip
, p. 53 - 58 (1999)
m-Mentha-3(8),6-diene (= isosylveterpinolene; 5), which has not been found in nature before, was shown by GC/MS analysis and co-injection with a synthetic sample to be present to the extent of 0.12-0.17% in black and green pepper oil. The synthetic reference 5 was prepared by deconjugation of 3- methylcyclohex-2-en-1-one (1), subsequent alkylation with lithium 2-lithio- 2-methylpropanoate, and decarboxylative dehydration of the resulting hydroxycarboxylic acid 3 employing dimethylformamide dimethyl acetal. On polar GC columns, 5 was eluted between p-cymene and terpinolene, and was characterized by an MS similar to that of terpinolene, but with the fragment m/z 121 (59, [M - Me]+) being less intense than that of the molecular ion at m/z 136 (67, M+). Since m-mentha-3(8),6-diene was also found to the extent of 0.24% in the headspace of ground black peppercorns, it can be considered to be of genuine natural origin, and thus is the first established example of a naturally occurring m-menthadiene.
Organocatalytic multicomponent α-methylenation/diels-alder reactions: A versatile route to substituted cyclohexenecarbaldehyde derivatives
Zou, Yue,Wang, Quanrui,Goeke, Andreas
experimental part, p. 5335 - 5345 (2009/05/28)
This article describes the design and optimization of an effective organocatalytic three-componentdomino α-methylenation/Diels-Alder reaction to produce vinyl-substituted cyclohexenecarboxaldehydes in a highly regioselective fashion. In these one-pot transformations, 2-formyl-1,3- butadienes (4) were prepared in situ from α,β-unsaturated aldehydes and formalin and were subsequently trapped with a variety of buta-l,3-dienes. The outcomes of the reactions were dependent on the electronic properties of the dienes. 1-Vinylcyclohexenecarbaldehydes 6 were formed by use of acyclic electron-rich dienes, while the initially formed cycloadducts of 4 with cyclopentadiene underwent Cope rearrangements, leading to the formation of tetrahydro-3H-indene-5-carbaldehyde compounds 7. The mechanisms involved in these reactions were deduced from experimental findings. Furthermore, the method was also extended to one-pot domino methylenation/ Diels-Alder reactions of dihydrofurans and dihydropyrans to yield spirocyclic lactols 22. In these reactions, the unstable intermediate hydroxyethyl and hydroxypropyl acroleins behaved as dienophiles, undergoing cycloaddition reactions with dienes with good yields and selectivities. The wide variety of functionalized 1-vinylcyclohex-3-enecarbaldehydes 6, 4-vinylcyclohex-l-enecarbaldehydes 7, and spiro lactols 22 generated through the use of these organocatalytic domino processes as a diversityoriented synthesis provided useful intermediates for the construction of novel odorants.
