499-71-8Relevant academic research and scientific papers
Biomimetic Transformation of p-Menthene Glucosides into p-Cymenes and Carvotanacetone
Pardo-Novoa, Julio C.,Arreaga-González, Héctor M.,Galván-Gómez, Sinuhé,Rodríguez-García, Gabriela,Del Río, Rosa E.,Cerda-García-Rojas, Carlos M.,Joseph-Nathan, Pedro,Gómez-Hurtado, Mario A.
, p. 485 - 491 (2019)
A biomimetic transformation of p-menthene glucosides into aromatic monoterpenoids that alluded to mechanisms for essential oil metabolism, which lines up with the precepts of molecular economy, is described. Acid treatment of (-)-(3S,4S,6R)-3,6-dihydroxy-1-menthene 3-O-β-d-glucopyranoside (1) and (-)-(3S,4R,5R,6S)-3,5,6-trihydroxy-1-menthene 3-O-β-d-glucopyranoside (2), from Ageratina glabrata, yielded p-cymene (7) and carvacrol (9). The stable oxidized intermediates (+)-(3S,4S,6R)-3,6-dihydroxy-1-menthene (3), (+)-(1S,4S,6R)-1,6-dihydroxy-2-menthene (4), (+)-(1R,4S,6R)-1,6-dihydroxy-2-menthene (5), (+)-(4S,6R)-yabunikkeol (6), (+)-(4S)-carvotanacetone (8), (+)-(1S,4S,5R,6R)-1,5,6-trihydroxy-2-menthene (15), (+)-(1R,4S,5R,6R)-1,5,6-trihydroxy-2-menthene (16), and the new (+)-(4S,5R,6S)-1(7),2-menthadiene (17) permitted establishment of the reaction mechanisms. The reactivity of the hydroxy groups of 4 and 5, as well as those of 15 and 16, was compared by acetylation reactions and supported by DFT calculations, revealing diminished reactivity in 4 and 15 due to the cis configuration of their hydroxy groups at C-1 and C-6. In addition, p-cymene (7) was detected as one of the major constituents of the essential oil of A. glabrata, which matches well with the biomimetic study.
On the Diastereoselectivity of the Complexation of Ketopinic Acid-Derived 2-Acyloxy-1,3-cyclohexadienes and the Configurational Stability of Dienol-Fe(CO)3Complexes. A Case Study
Adler, Andreas,Botov, Svetlana,Hemmersbach, Lars,Neud?rfl, J?rg-Martin,Romanski, Steffen,Schmalz, Hans-Günther
supporting information, p. 2909 - 2914 (2021/08/30)
In the course of an attempt to synthesize 2-acyloxycyclohexa-1,3-diene-Fe(CO)3 complexes in nonracemic form, we reinvestigated the "fully diastereoselective"Fe(CO)3 complexation of (S,S)-2-ketopinoyloxy-1,3-cyclohexadiene, which had been described by Yeh and co-workers (Organometallics 2001, 20, 289-295). However, after cleaving off the chiral auxiliary unit, we only obtained racemic complexes, also for a related substrate. For this reason, we performed control experiments to exclude possible racemization mechanisms and confirmed the configurational integrity of the dienol-Fe(CO)3 intermediates using stereochemically defined dihydrocarvone-derived complexes. We finally could show that the complexation described by Yeh actually proceeds without any detectable diastereoselectivity. At the end, the virtually inseparable diastereomers of the chiral complexation products could be distinguished by careful NMR and chiral HPLC analyses.
Total Synthesis of (-)-Daphnezomines A and B
Li, Chao,Li, Luyang,Lu, Yunan,Wu, Jinbao,Xu, Guangpeng
supporting information, p. 15240 - 15245 (2020/10/20)
Daphnezomines A and B are structurally unusual Daphniphyllum alkaloids that contain a unique aza-adamantane core skeleton. Herein, a modular approach to these alkaloids is presented that exploits a diverse array of reaction strategies. Commencing from a chiral pool terpene-(S)-carvone, the azabicyclo[3.3.1]nonane backbone, which occurs widely in Daphniphyllum alkaloids, was easily accessed through a Sharpless allylic amination and a palladium-catalyzed oxidative cyclization. A protecting group enabled a stereoselective B-alkyl Suzuki-Miyaura coupling sequence and an Fe-mediated hydrogen atom transfer (HAT)-based radical cyclization were then applied to construct C6 and C8 stereocenters. A final epimer locking strategy enabled the assembly of the highly congested aza-adamantane core, thereby achieving the first total synthesis of (-)-daphnezomines A and B in 14 steps.
Total Synthesis of (+)-Sarcophytin
Nannini, Leonardo J.,Nemat, Suren J.,Carreira, Erick M.
supporting information, p. 823 - 826 (2017/12/26)
A total synthesis of the cembranoid (+)-sarcophytin is presented, featuring a Diels–Alder cycloaddition of an enone as the dienophile with an ester-derived dienoate. The study highlights a peculiar geometric preference for the Z dienoate to furnish the cy
Microwave assisted bi-functional activation of β-bromo-tert-alcohols
Kannan, Nandini,Rangaswamy, Manjunatha Javagal,Kemapaiah, Bettadaiah Bheemanakere
, p. 1405 - 1410 (2015/11/09)
Microwave-assisted dehydration-oxidation of β-bromo-tert-alcohols to afford 2,3-unsaturated ketones in good yield is reported. The reaction of substrates with DMSO in 1:1 ratio (w/v) is promoted by ZnS in a solvent-free condition. A concurrent bi-functional activation of trans-vicinal bromo- and hydroxyl groups with ZnS is elucidated. This is a new observation under microwave and applies to β-bromo-tert-alcohols derived from 1,4-disubstitued-1-cyclohexenes. It is very useful in the synthesis of 2,3-unsaturated ketones derived from monoterpenes which are valuable flavour compounds. [Figure not available: see fulltext.]
Platinum Nanoparticles Stabilized by Glycerodendrimers: Synthesis and Application to the Hydrogenation of α,β-Unsaturated Ketones under Mild Conditions
Menot, Bérengère,Salmon, Lionel,Bouquillon, Sandrine
supporting information, p. 4518 - 4523 (2015/10/06)
Air-stable platinum nanoparticles stabilized by glycerodendrimers were prepared in water and analyzed by TEM. These platinum nanoparticles showed good catalytic activity for the reduction of α,β-unsaturated ketones to saturated ketones at room temperature in water or in water/THF (1:1) under H2 (101.3 kPa). The catalytic species was recovered and recycled several times.
Asymmetric synthesis of the tricyclic core of calyciphylline A-type alkaloids via intramolecular [3 + 2] cycloaddition
Wang, Lu,Xu, Chen,Chen, Li,Hao, Xiaojiang,Wang, David Zhigang
supporting information, p. 1076 - 1079 (2014/03/21)
Asymmetric synthesis of the [5-6-7] tricyclic system common to the Calyciphylline A-type alkaloids is reported, featuring Overman rearrangement, Heck cyclization, intramolecular [3 + 2] cycloaddition, diastereoselective hydrogenation, and Claisen rearrangement as strategic events. The approach is capable of installing the crucial carbonyl functionality as well as multiple stereogenic centers within a congested polycyclic ring skeleton.
Grafted non-ordered niobium-silica materials: Versatile catalysts for the selective epoxidation of various unsaturated fine chemicals
Tiozzo, Cristina,Bisio, Chiara,Carniato, Fabio,Guidotti, Matteo
, p. 49 - 57 (2014/08/18)
Two kinds of niobium(V)-silica catalysts for the selective epoxidation were synthesised by post-synthesis modification of non-ordered mesoporous silica supports, starting from niobocene dichloride via solvent-less organometallic precursor dry impregnation
Rapid construction of [5-6-7] tricyclic ring skeleton of calyciphylline alkaloid daphnilongeranin B
Xu, Chen,Liu, Zheng,Wang, Huifei,Zhang, Bo,Xiang, Zheng,Hao, Xiaojiang,Wang, David Zhigang
scheme or table, p. 1812 - 1815 (2011/06/19)
A concise photochemical [2 + 2] cycloaddition-Grob fragmentation sequence sets the common tricyclic ring skeletons of the Calyciphylline A-type alkaloids, particularly those in daphnilongeranins, daphniyunnines, and daphniglaucins.
Dauben-Michno oxidative transposition of allylic cyanohydrins - Enantiomeric switch of (-)-carvone to (+)-carvone
Hudlicky, Jason R.,Werner, Lukas,Semak, Vladislav,Simionescu, Razvan,Hudlicky, Tomas
, p. 535 - 543 (2011/10/03)
Allylic cyanohydrins were subjected to Dauben-Michno oxidation at low temperatures to provide β-cyanoenones in good to excellent yields. The potential of this oxidative transposition as a means of an enantiomeric switch of enones containing a latent plane of symmetry was tested by conversion of (-)-carvone to its enantiomer.
