10236-06-3Relevant academic research and scientific papers
Efficient photochemical synthesis of 2-vinylcyclopropanecarbaldehydes, precursors of cyclopropane components present in pyrethroids, by using the oxa-di-π-methane rearrangement
Armesto, Diego,Ortiz, Maria J.,Agarrabeitia, Antonia R.,El-Boulifi, Noureddin
experimental part, p. 8690 - 8697 (2011/01/04)
A comparative study on the triplet photoreactivity of a series of β,γ,δ,ε-unsaturated aldehydes 14a-f and 15, using 3-methoxyacetophenone and 4-phenylbenzophenone as sensitizers, has been carried out. When 3-methoxyacetophenone is used as the triplet sensitizer, the aldehydes undergo oxa-di-π-methane rearrangement (ODPM) to afford the corresponding cyclopropanecarbaldehydes 16a-f and 17 in yields ranging from 14% to 62% in addition in most cases to products resulting from decarbonylation. However, when 4-phenylbenzophenone is used as the photosensitizer ODPM products are obtained exclusively in almost quantitative yield. These are additional examples of the recently described, unexpected influence of the nature of the triplet sensitizer on the photoreactivity of organic compounds.
Stereocontrolled synthesis of 1,3,5-triols by an iteration of asymmetric dihydroxylation and deoxygenation
Walleser, Patrick,Brueckner, Reinhard
experimental part, p. 4802 - 4822 (2010/10/20)
Asymmetrie dihydroxylation of the Cγ=Cδ bonds in trans-configured α, β, γ, δ-unsaturated esters, carbonate formation, and Pd°-catalyzed deoxygenation of Cγ provided α, β-unsaturated δ-hydroxy esters. Protection and chain-extension provided the corresponding α, β-unsaturated ketones. Their asymmetric dihydroxylation in the presence of phenylboronic acid delivered dioxaborolanes. SmBr2-mediated deoxygenation of Ca, followed by Narasaka-Prasad and Claisen-Tishchenko reductions, respectively, selectively provided monoprotected 1,3syn, 3,5syn-, 1,3syn, 3,5anti-, 1,3anti, 3.5syn-, and 1,3anti, 3,5anticonfigured 1,3,5-triols. Enones with a bulky OSiR3 group at Cδ were dihydroxylated with significantly poorer syn (vs. anti) selectivities. Dominating reagent control modulated by opposing ( mismatched case ) or enhancing ( matched case ) substrate control, respectively, might be responsible.
The Synthesis of Two Furan-Based Analogues of the α′,β ′-Epoxy Ketone Proteasome Inhibitor Eponemycin
Bennacer, Bibia,Trubuil, Dominique,Rivalle, Christian,Grierson, David S.
, p. 4561 - 4568 (2007/10/03)
Myers's methodology for enantioselective amino acid synthesis was employed to prepare the N-Boc didehydroleucine amide derivative 15 and to effect its conversion into the acylfuran intermediate 17. Coupling of 19 (R = H) with N-(isooctanoyl)serine provided the furan-based analogue 4 of eponemycin (de = 96 %), a peptide epoxide with potent cytotoxic and anti-angiogenesis properties. In an identical fashion the corresponding unsaturated analogue 5 of eponemycin was prepared (de = 48%). Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
Stereoselective Synthesis of Ethyl (2E,4E)-Alkadienoates from Ethyl Sulfolane-2-carboxylate
Saigo, Kazuhiko,Kudo, Kazuaki,Hashimoto, Yukihiko,Kihara, Nobuhiro,Hasegawa, Masaki
, p. 1203 - 1206 (2007/10/02)
α,β,γ,δ-Unsaturated esters were conveniently synthesized from ethyl sulfolane-2-carboxylate through alkylation and oxidation followed by the retro Diels-Alder reaction of the resulting 3-sulfolene derivatives.The reaction proceeded with high E,E-selectivity.
Synthesis of functionalized bicycloocta-2,6-dienes by thermal rearrangement of substituted 6-exo-(1-alkenyl)bicyclohex-2-ene systems
Piers, Edward,Jung, Grace L.,Ruediger, Edward H.
, p. 670 - 682 (2007/10/02)
Thermolysis of each of the enol silyl ethers 31-35 affords, cleanly and efficiently, the bicyclooctadienes 36-40, respectively.Similarly, thermal rearrangement of the enol silyl ether 50 provides the diene 51.Hydrolysis of 36, 37, and 39, and decar
THERMAL REARRANGEMENT OF DIVINYLCYCLOPROPANE SYSTEMS. PREPARATION OF FUNCTIONALIZED, STEREOCHEMICALLY DEFINED BICYCLIC AND TRICYCLIC PRODUCTS CONTAINING THE BICYCLOOCTANE SKELETON
Piers, Edward,Jung, Grace L.,Moss, Neil
, p. 3959 - 3962 (2007/10/02)
A study involving the preparation and thermolysis of substituted 6-exo-(1-alkenyl)bicyclohex-2-ene systems (14, 15, 23, 29, 40) shows (a) that C-8 functionalized bicycloocta-2,6-dienes can be prepared readily via this methodology (14 -> 16; 15 -> 17), (b) that the rearrangement reaction is stereospecific even when the 6-(1-alkenyl) group is substituted with a sterically bulky isopropyl group (23 -> 24; 29 -> 30), and (c) that the method can be extended to include the preparation of tricyclic systems (40 -> 41).
Total Synthesis of (+/-)-Dendrobine
Roush, William R.
, p. 1390 - 1404 (2007/10/02)
A total synthesis of (+/-)-dendrobine is described. (E,E,E)-Triene 9a, available stereoselectively in six steps from methyl 4-(diethylphosphono)crotonate, cyclizes by an intramolecular Diels-Alder reaction to afford 75-83percent of a mixture of four perhydroindanols containing 83percent of endo isomers 8a and 8b.Epimers 8a and 8b were transformed into nitrile 25 by two separate routes, each of which involves epimerization of C4, oxidation, angular methylation, and reductive cyanation.Nitrile 25 served as a precursor of amino ester 3 by two separate routes, the most efficient of which proceeded via bromolactone 40.Epoxidation of the trichloroethylurethane 58 prepared from 3 afforded a mixture of two epoxides, both of which were utilized in the synthesis.The minor epoxide, 59 (38-40percent yields), was transformed into dendrobine via methyl ketodendrobinate 57, while the major epoxide 60 (45-48percent yields) was recycled to 58.Additional strategies for the synthesis of dendrobine from 3 are discussed.
