1002-36-4Relevant articles and documents
The first synthesis of tonkinecin, an annonaceous acetogenin with a C-5 carbinol center
Hu, Tai-Shan,Yu, Qian,Lin, Qi,Wu, Yu-Lin,Wu, Yikang
, p. 399 - 401 (1999)
(formula presented) Reported herein is the first synthetic approach to tonkinecin (1) which uses a palladium-catalyzed cross-coupling reaction between the tetrahydrofuran unit (4) and the butenolide (3) as the key step for constructing the backbone of 1. The stereogenic centers at C-5, C-21, C-22, and C-36 were derived from D-xylose, D-glucose, and L-lactate, respectively, whereas those at C-17, and C-18 were generated using Sharpless asymmetric dihydroxylation.
Synthesis of medium- and large-sized lactones in an aqueous-organic biphasic system
Kinoshita, Hidenori,Shinokubo, Hiroshi,Oshima, Koichiro
, p. 2397 - 2400 (2005)
(Chemical Equation Presented) Saving solvent: An aqueous-ethyl acetate biphasic system allows an efficient synthesis of medium- and large-sized lactones by an intramolecular Tsuji-Trost reaction (see scheme, n = 1-5). The macrocyclization protocol does not require a large quantity of solvents or a slow-addition technique.
Gold(I)-Catalyzed Angle Strain Controlled Strategy to Furopyran Derivatives from Propargyl Vinyl Ethers: Insight into the Regioselectivity of Cycloisomerization
Jin, Shengfei,Jiang, Chongguo,Peng, Xiaoshi,Shan, Chunhui,Cui, Shanshan,Niu, Yuanyuan,Liu, Yang,Lan, Yu,Liu, Yongxiang,Cheng, Maosheng
, p. 680 - 683 (2016)
A unique strategy for the regiospecific synthesis of bicyclic furopyran derivatives has been developed via a gold(I)-catalyzed propargyl-Claisen rearrangement/6-endo-trig cyclization of propargyl vinyl ethers. The introduction of angle strain into the substrates significantly altered the reaction's regioselectivity. Insight into the regioselectivity of the cycloisomerization was obtained with density functional theory calculations. (Chemical Equation).
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Toussaint,Wenzke
, p. 668 (1935)
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Enantioselective Rhodium-Catalyzed Dimerization of ω-Allenyl Carboxylic Acids: Straightforward Synthesis of C2-Symmetric Macrodiolides
Steib, Philip,Breit, Bernhard
, p. 6572 - 6576 (2018)
Herein, we report on the first enantioselective and atom-efficient catalytic one-step dimerization method to selectively transform ω-allenyl carboxylic acids into C2-symmetric 14- to 28-membered bismacrolactones (macrodiolides). This convenient asymmetric access serves as an attractive route towards multiple naturally occuring homodimeric macrocyclic scaffolds and demonstrates excellent efficiency to construct the complex, symmetric core structures. By utilizing a rhodium catalyst with a modified chiral cyclopentylidene-diop ligand, the desired diolides were obtained in good to high yields, high diastereoselectivity, and excellent enantioselectivity.
Synthesis of polyacetylenic acids isolated from Heisteria acuminata
Zeni, Gilson,Panatieri, Rodrigo B.,Lissner, Eliseo,Menezes, Paulo H.,Braga, Antonio L.,Stefani, Helio A.
, p. 819 - 820 (2001)
matrix presented Four linear polyacetylenic compounds were synthesized. Pentadeca-6,8,10-triynoic acid 1 and octadeca-8,10,12-triynoic acid 2 were synthesized by using acetylene coupling reactions. The syntheses of (Z)-hexadec-11-en-7,9-diynoic acid 3 and (Z)-octadec-12-en-7,9-diynoic acid 4 by using vinylic telluride coupling reactions were accomplished.
A facile, catalytic, and environmentally benign method for selective deprotection of teri-butyldimethylsilyl ether mediated by phosphomolybdic acid supported on silica gel
Kishore Kumar,Baskaran, Sundarababu
, p. 4520 - 4523 (2005)
An environmentally benign PMA supported on SiO2 is found to be an efficient catalyst for the chemoselective deprotection of TBDMS ethers under very mild conditions. Various labile functional groups such as isopropylidene acetal, OTBDPS, OTHP, Oallyl, OBn, alkene, alkyne, OAc, OBz, N-Boc, N-Cbz, N-Fmoc, mesylate, and azide are found to be stable under the reaction conditions. This "truly catalytic" heterogeneous reaction does not require aqueous workup, and the supported catalyst and the solvent can be readily recovered and recycled.
An improved synthesis route to functionalized 2-alkyn-1-ylboronates: Useful intermediates for the preparation of α-allenic alcohols
Roy, Chandra D.,Soundararajan, Raman,Brown, Herbert C.
, p. 241 - 249 (2008)
Functionalized 2-alkyn-1-ylboronates were successfully prepared in good yields by reacting various acyclic and cyclic (iodomethyl)boronates with various alkynyllithium salts. Amongst various (iodomethyl)boronates studied, 2-(iodomethyl)-1,3,2-dioxa-4,4,5,5-tetramethylborolane provided improved chemical yields of 2-alkyn-1-ylboronates with pyran- and triisopropylsilyl- substituted alkynyllithium salts. 2-Alkyn-1-ylboronate bearing an acid sensitive structure (pyran) was successfully synthesized which would be very difficult to achieve under previously reported reaction conditions. The exceptionally rapid rearrangement of the "ate" complex derived from the pinacol (iodomethyl)boronate, suppression of the side product formation, and the stability of the pinacol 2-alkyn-1-ylboronate are some of the notable merits of this protocol. This new procedure offers a simple and convenient alternative route to the existing methodologies, in terms of the milder reaction conditions, functional group compatibility, and the ease of the operation. The synthesis scope of this class of 2-alkyn-1-ylboronates was demonstrated by reacting the pinacol 2-alkyn-1-ylboronate with benzaldehyde, which yielded the α-allenic alcohol in good yield and regioselectivity.
Catalytic Generation of Rhodium Silylenoid for Alkene-Alkyne-Silylene [2 + 2 + 1] Cycloaddition
Ohmura, Toshimichi,Sasaki, Ikuo,Suginome, Michinori
supporting information, p. 1649 - 1653 (2019/03/20)
An alkene-alkyne-silylene [2 + 2 + 1] cycloaddition takes place in the rhodium-catalyzed reaction of 1,6-enynes with borylsilanes bearing an alkoxy group on the silicon atoms, which react as synthetic equivalents of silylene. The reaction proceeds efficiently in 1,2-dichloroethane at 80-110 °C in the presence of a rhodium catalyst bearing bis(diphenylphosphino)methane (DPPM) as a ligand to afford 1-silacyclopent-2-enes in good to high yields.
Synthesis of (5Z,7E)-dodecane-5,7-diene-1-alcohol as well as acetate and propionate thereof
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Paragraph 0026-0028, (2019/03/28)
The invention belongs to the technical field of insect pheromone synthesis, and discloses a new method for synthesizing (5Z,7E)-dodecane-5,7-diene-1-alcohol as well as acetate and propionate thereof.The method takes propynol as an initial raw material to be subjected to coupling with 1-bromobutane to generate 2-heptyne-1-alcohol, triple bond is reduced to be E-type double bond through LiAlH4, 2-heptyne-1-alcohol is oxidized to be olefine aldehyde through PDC, olefine aldehyde reacts with a Wittig reagent (5-ethyoxyl-5-oxopentyl)triphenyl phosphonium bromide to produce (5Z,7E)-dodecane-5,7-dienoic acid ethyl ester which is reduced by LiAlH4 to obtain (5Z,7E)-dodecane-5,7-diene-1-alcohol, (5Z,7E)-dodecane-5,7-diene-1-alcohol reacts with acetyl chloride and propionyl chloride finally to obtain (5Z,7E)-dodecane-5,7-diene-1-alcohol acetate and (5Z,7E)-dodecane-5,7-diene-1-alcohol propionate. The method utilizes LiAlH4 to reduce the triple bond to be the E-type double bond, and utilizes theWittig reaction of the Wittig reagent with the tail end provided with ester group and aldehyde to directly build the Z-type double bond, the synthesis route is simple, convenient and efficient, and the reaction condition is moderate and environmentally friendly.
