20085-72-7Relevant academic research and scientific papers
UNIQUE HALOGEN-INDUCED CYCLIZATIONS, REAGENTS THEREFOR, AND COMPOUNDS PRODUCED THEREBY
-
Page/Page column 85, (2012/04/04)
This disclosure is related to halonium compounds useful for cyclization of polyenes, alkenoic acids, and alkenyl alkyl ethers, and halogenation of aromatic compounds. The synthesis of such halonium compounds, compounds made using such halonium compounds, and synthesis of natural compounds, including decalins, using the halonium compounds is also disclosed. A representative halonium compound of the disclosure is: Formula (I).
Simple reagents for direct halonium-induced polyene cyclizations
Snyder, Scott A.,Treitler, Daniel S.,Brucks, Alexandria P.
supporting information; experimental part, p. 14303 - 14314 (2011/01/04)
Although there are many reagent combinations that can initiate polyene cyclizations, simple electrophilic halogen sources have not yet proven broadly effective as promoters of such processes. Herein is described a readily prepared and stable class of reagents capable of effecting such transformations for a wide range of electron-rich and -deficient terpenes derived from geraniol, farnesol, and nerol, thereby enabling the effective synthesis of a diverse array of complex chlorine-, bromine-, and iodine-containing polycyclic frameworks. Efforts to date have led to the first racemic laboratory total synthesis and structural revision of the anti-HIV natural product peyssonol A as well as an efficient and concise inaugural total synthesis of peyssonoic acid A. They have also permitted formal racemic total syntheses of aplysin-20, loliolide, K-76, and stemodin to be achieved through routes that are typically shorter, higher-yielding, and more environmentally conscious than previous efforts. Preliminary attempts to use chiral forms of the reagent class for enantioselective alkene halogenation are also described.
Synthesis of farnesol isomers via a modified wittig procedure
Yu, Jose S.,Kleckley, Troy S.,Wiemer, David F.
, p. 4803 - 4806 (2007/10/03)
(Chemical Equation Presented) The four olefin stereoisomers of farnesol have been synthesized from readily available nerylacetone or commercial geranylacetone. A new variation on the use of β-oxido ylides favored the (2Z)-stereoisomers, whereas the (2E)-isomers were obtained through a classical Horner-Wadsworth-Emmons condensation with triethyl phosphonoacetate and reduction of the resulting ester.
Z-Stereoselective Peterson olefination of ketones
Grigorieva, N. Ya.,Pinsker, O. A.,Buevich, A. V.,Moiseenkov, A. M.
, p. 492 - 499 (2007/10/02)
A highly-stereoselective method (90percent of the Z-isomer) was developed for the Peterson olefination of ketones with nerylacetone (1) as an example.The method is based on the introduction of a PhS group, which is removed after completion of the reaction, at the ketone C(3) atom. - Keywords: olefination of ketones, stereoselective synthesis, Peterson reaction, 2Z- and 2E-4-phenylthiofarnesoles and 2Z- and 2E-4-phenylthiofarnesoates
OZONOLYSIS OF ALKENES AND REACTIONS OF POLYFUNCTIONAL COMPOUNDS. XXXVI. SYNTHESIS OF ETHYL 3,7,10-TRIMETHYL-2E,4E-DODECADIENOATE
Odinokov, V. N.,Kukovinets, O. S.,Zainullin, R. A.,Sultanmuratova, V. R.,Tolstikov, G. A.
, p. 1230 - 1237 (2007/10/02)
Hydroprene was obtained with an overall yield of 16percent in the form of a 77:23 mixture of 2E,4E and 2Z,4E isomers by ozonolysis of 1,5-dimethyl-1-cyclooctene and selective transformations of the 4-methyl-1,1-dimethoxy-8-oxononane, including ethoxycarbonylmethylenation of the keto group, alkylation of the formyl group by isopropylmagnesium bromide followed by deoxygenation, and allylic bromination-dehydrobromination.The individual 2E,4E isomer was isolated by HPLC.
Synthesis of Terpenes Containing the Bicycloheptane Ring System by the Intramolecular Cycloaddition Reaction of Vinylketenes with Alkenes. Preparation of Chrysanthenone, β-Pinene, β-cis-Bergamotene, β-trans-Bergamotene, β-Copaene, and β-Ylangene and Lemnalol
Kulkarni, Yashwant S.,Niwa, Maho,Ron, Eyal,Snider, Barry B.
, p. 1568 - 1576 (2007/10/02)
Treatment of geranoyl chloride (20) with triethylamine in toluene at reflux gave the vinylketene 21 which underwent a cycloaddition to give 7,7-dimethyl-2-methylenebicycloheptan-6-one (24) in 43percent yield.Isomerization over Pd gave chrysanthenone (6) in quantitative yield.Wolf-Kischner reduction gave β-pinene (5) in 70percent yield.A similar sequence of reactions starting from (Z,E)- and (E,E)-farnesoyl chloride gave ketones 51 and 57, which were converted to β-cis-bergamotene (8) and β-trans-bergamotene (9), respectively. β-Copaene (10) and β-ylangene (11) were prepared from 57 by a three-step sequence.Treatment of the imidazole 59 with tri-n-butyltin hydride in toluene at reflux gave a 46percent yield of a 1:1 mixture of 10 and 11.Selenium dioxide oxidation of 11 gave the antitumor agent lemnalol.The mechanisms of the regiospecific ketene generation and the cycloaddition reaction have been explored, and the reactivity of the novel bicycloheptanones has been examined.
