65489-13-6Relevant academic research and scientific papers
Synthesis of Pyranocyclopentaindolines Representing the Western Sections of Janthitrem B, JBIR-137, and Shearinine G
Fresia, Marvin,Lindel, Thomas
supporting information, (2022/02/05)
The synthesis of the ABCD tetracyclic partial structures of the fungal indole diterpenes janthitrem B, JBIR-137, and shearinine G is reported. The route starts from 5-formylated indoline that is coupled to a dihydropyran moiety, followed by Prins cyclization. A diene was obtained that was oxygenated in a divergent manner. The hydroxylated tetracyclic western half of janthitrem B was obtained in eight steps and 10 % overall yield. We also share our experience with alternative approaches passing via alkynylated precursors. This includes the gold-catalyzed cycloisomerization of a 6-ethynyl-5-prenylindoline.
Rhodium-Catalyzed Parallel Kinetic Resolution of Racemic Internal Allenes Towards Enantiopure Allylic 1,3-Diketones
Hilpert, Lukas J.,Breit, Bernhard
supporting information, p. 9939 - 9943 (2019/06/24)
A rare case of a parallel kinetic resolution of racemic 1,3-disubstituted allenes by means of a rhodium-catalyzed addition to 1,3-diketones furnishing enantiopure allylic 1,3-diketones is described. Mechanistic experiments demonstrate that the different allene enantiomers react in parallel to either the diastereomeric E- or Z-allylic 1,3-diketones with the same absolute configuration of the newly formed stereogenic center. A broad substrate scope demonstrates the synthetic utility of this new method.
Unsaturated aldehydes as potential lilial replacers
Schroeder, Martin,Mathys, Marion,Ehrensperger, Nadja,Büchel, Michelle
, p. 1651 - 1673 (2015/02/19)
A series of Claisen rearrangements was undertaken in order to find a replacement for Lilial (= 3-(4-(tert-butyl)phenyl)-2-methylpropanal), a high-tonnage perfumery ingredient with a lily-of-the-valley odour, which is a CMR2 material [1]. 5,7,7-Trimethyl-4-methyleneoctanal (10), the synthesis of which is described, became the main lead. It possesses an odour which is very close to that of Lilial but lacks its substantivity. Aldehydes with higher molecular weights than that of 10 were, therefore, synthesised in order to boost substantivity and to understand the structural requirements for a 'Lilial' odour. The aldehydes were obtained via Claisen rearrangements of 'exo-methylidene' vinyl ethers, allenyl vinyl ethers, or allenyl allyl ethers. Alternatively, coupling of terminal alkynes with allyl alcohols led to the desired aldehydes. Derivatives of 10 and their sila analogues were also synthesised. The olfactory properties of all synthesised molecules were evaluated for possible structure-odour relationships (SOR).
Reactivity pattern of bis(propargyloxy) disulfides: Tandem rearrangements and cyclizations
Braverman, Samuel,Pechenick-Azizi, Tatiana,Gottlieb, Hugo E.,Sprecher, Milon
experimental part, p. 1741 - 1750 (2011/07/09)
Thirty-five substituted bis(propargyloxy) disulfides were successfully prepared in good to excellent yields, and their reactivity was found to be strongly dependent on the substitution pattern of the reactant. Inter alia they undergo surprising tandem sigmatropic rearrangements and cycloadditions. Three heretofore unknown product types were isolated and fully characterized: 6,7-dithiabicyclo[3.1.1]heptan-2-one 6-oxide derivatives, two isomeric 1,2-dithiete 1,1-dioxides (α,β-unsaturated four-membered cyclic thiosulfonates) from bis(propargyloxy) disulfides with α- or γ-alkyl-substituted propargyl groups, and two isomeric 2-oxa-5,7-dithiabicyclo[2.2.1]heptane 5-oxides from bis(propargyloxy) disulfides with α-tert-butyl- or α,α-dialkyl-substituted propargyl groups. Georg Thieme Verlag Stuttgart - New York.
Enantioselective copper-catalysed propargylic substitution: Synthetic scope study and application in formal total syntheses of (+)-anisomycin and (-)-cytoxazone
Detz, Remko J.,Abiri, Zohar,Le Griel, Remi,Hiemstra, Henk,Van Maarseveen, Jan H.
experimental part, p. 5921 - 5930 (2011/06/26)
A copper catalyst with a chiral pyridine-2,6-bisoxazoline (pybox) ligand was used to convert a variety of propargylic esters with different side chains (R=Ar, Bn, alkyl) into their amine counterparts in very high yields and with good enantioselectivities (up to 90% enantiomeric excess (ee)). Different amine nucleophiles were applied in the reactions and the highest enantioselectivities were obtained for aniline and its analogues. Interestingly, some carbon nucleophiles could also be used and with indoles excellent ee values were obtained (up to 98% ee). The versatility of the propargylic amines obtained was demonstrated by their further elaboration to formal total syntheses of the antibiotic (+)-anisomycin and the cytokine modulator (-)-cytoxazone. Copyright
Total syntheses of the furanosesquiterpenes crassifolone and dihydrocrassifolone via an Au(I)-catalysed intramolecular Michael addition reaction
Menon, Rajeev S.,Banwell, Martin G.
supporting information; experimental part, p. 5483 - 5485 (2011/02/18)
The racemic modifications of title natural products 1 and 2 have been synthesised for the first time. The key step was the Au(i)-catalysed conversion of the furanyl-substituted ynone 13 into the annulated furan 14.
Synthesis of pyridazine-based scaffolds as α-helix mimetics
Volonterio, Alessandro,Moisan, Lionel,Rebek Jr., Julius
, p. 3733 - 3736 (2008/02/12)
The synthesis of several amphiphilic, nonpeptidic scaffolds that mimic the presentation of i, i + 3 or i + 4, and i + 7 residues of a peptide α-helix is described. The approach uses a pyridazine core, and the synthesis involves only a few steps and minimi
Synthesis of azide-alkyne fragments for 'click' chemical applications; formation of oligomers from orthogonally protected trialkylsilyl-propargyl azides and propargyl alcohols
Montagnat, Oliver D.,Lessene, Guillaume,Hughes, Andrew B.
, p. 6971 - 6974 (2007/10/03)
A series of orthogonally protected 1,4-disubstituted-1,2,3-triazoles were prepared from the corresponding alkynols and trialkylsilyl-propargyl azides via 1,3-dipolar cycloaddition. These cycloadducts were selectively deprotected and extended in a stepwise fashion via further 'click' reactions to form oligomeric peptidomimetic compounds. This methodology gives access to triazole-based peptidomimetics in a controlled fashion and lays the foundation for a fragment-based approach to drug discovery.
Syntheses and synthetic applications of stannylated allylic alcohols
Kazmaier, Uli,Lucas, Simon,Klein, Manuela
, p. 2429 - 2433 (2007/10/03)
Allenyl carbinols undergo regioselective hydrostannation in the presence of MoBl3, a catalyst originally developed for the hydrostannation of alkynes, giving rise to allyl stannanes. These allyl stannanes can easily be converted into useful synthetic building blocks such as allyl iodides or vinyl epoxides.
The Synthesis of 9-Substituted N-Benzyl-8-azabicyclonon-4-en-7-ones by the Intramolecular Diels-Alder Reaction
Brettle, Roger,Jafri, Iftikhar A.
, p. 387 - 394 (2007/10/02)
The intramolecular thermal cyclisation of N-allyl-N-benzylpenta-2(E),4-dienamide in refluxing NN-dimethylformamide gives N-benzyl-cis- and trans-8-azabicyclonon-4-en-7-one; N-allyl-N-benzylhexa-2(E),4(E)-dienamide gives (1RS, 3RS, 6SR)-3-methyl- an
