1655-05-6Relevant academic research and scientific papers
Photosensitized Cis/Trans Izomerization of 1-(1-Propenyl)cycloalkenes
Inman, Wayne D.,Sanchez, Kenneth A. J.,Chaidez, Manuel A.,Paulson, Donald R.
, p. 4872 - 4881 (1989)
The photosensitized cis/trans isomerization of a series of 1-(1-propenyl)cycloalkenes is reported.A plot of the photostationary state trans/cis ratio vs the sensitizer triplet energy for 1-(1-propenyl)cyclopentene shows a constant trans/cis ratio of ca. 1.0 with high-energy sensitizers (ET>61 kcal/mol).The plot shows one maxima at ET ca. 55 kcal/mol with low-energy sensitizers (ET61 kcal/mol).This type of plot is very similar to those obtained with acyclic dienes such as piperylene.The 1-(1-propenyl)cyclohexene system shows a similar plot with high-energy sensit izers, but with low-energy sensitizers this system shows two maxima occurring at 56 and 47 kcal/mol, respectively.This double-maxima plot is rationalized by an unsually low trans/cis decay ratio for the s-cis relaxed triplet state of the 1-(1-propenyl)cyclohexene system.This double maxima is not observed in other diene systems due to a high trans/cis decay ratio for their s-cis relaxed triplet states.The photosensitized cis/trans isomerization of 2-ethylidene-10-methyl-1(9)-octalin was also studied as a model for a conformationally locked s-trans system.The 1-(1-propenyl)cycloheptene system undergoes photosensitized cis/trans isomerization, but photostationary cis/trans isomerization data could not be obtained due to a very efficient photosensitized dimerization of this diene system.
Borylation of propargylic substrates by bimetallic catalysis. Synthesis of allenyl, propargylic, and butadienyl bpin derivatives
Zhao, Tony S. N.,Yang, Yuzhu,Lessing, Timo,Szabó, Kálmán J.
, p. 7563 - 7566 (2014/06/10)
Bimetallic Pd/Cu and Pd/Ag catalytic systems were used for borylation of propargylic alcohol derivatives. The substrate scope includes even terminal alkynes. The reactions proceed stererospecifically with formal S N2′ pathways to give allenyl boronates. Opening of propargyl epoxides leads to 1,2-diborylated butadienes probably via en allenylboronate intermediate.
Palladium-catalyzed methylation of alkynyl C(sp)-H bonds with dimethyl sulfonium ylides
Liu, Yan-Yun,Yang, Xu-Heng,Huang, Xiao-Cheng,Wei, Wen-Ting,Song, Ren-Jie,Li, Jin-Heng
, p. 10421 - 10426 (2013/11/06)
A novel palladium-catalyzed methylation protocol for the synthesis of methyl-functionalized internal alkynes has been established. This methylation method is achieved through a C(sp)-C(sp3) bond formation process and represents a new synthetic application of sulfonium ylides.
Combined rhodium/gold catalysis: From propargyloxiranes to 2,5-dihydrofurans in one pot
Aksin-Artok, Oezge,Krause, Norbert
supporting information; experimental part, p. 385 - 391 (2011/04/18)
A new and efficient one-pot synthesis of 2,5-dihydrofurans from propargyloxiranes and arylboronic acids takes advantage of sequential rhodium-gold catalysis. The transformation proceeds with center-to-axis-to- center chirality transfer and tolerates a wide variety of electron-accepting or electron-withdrawing substituents at the arylboronic acid, as well as cyclic or acyclic propargyloxiranes.
Synthesis of α-hydroxyallenes by copper-catalyzed S N2′substitution of propargylic dioxolanones
Tang, Xiaoping,Woodward, Simon,Krause, Norbert
experimental part, p. 2836 - 2844 (2009/09/29)
A new catalytic method for the synthesis of α-hydroxyallenes is described. Efficient SN2′ substitution of propargylic dioxolanones has been achieved with a copper(I)/P(OBu)3 catalyst: using Grignard reagents as the nucleophiles. The
Rhodium-catalyzed synthesis of indenols by regioselective coupling of alkynes with ortho-carbonylated arylboronic acids
Shintani, Ryo,Okamoto, Kazuhiro,Hayashi, Tamio
, p. 1294 - 1295 (2007/10/03)
A rhodium/diene-catalyzed regioselective synthesis of indenols has been developed through the coupling of alkynes with ortho-carbonylated arylboronic acids. These reactions proceed under mild conditions in uniformly high yield and regioselectivity. The re
Silacyclobutene compounds, methods of preparing same, and polymers formed therefrom
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, (2008/06/13)
A silacyclobutene compound having the formula: wherein R1 and R2 are independently chloro, triorganosiloxy, organooxy, triorganosilyl, or a monovalent hydrocarbon group; R3 is a monovalent hydrocarbon group free of conjugated aliphatic unsaturation or triorganosilyl; R5 is hydrogen or a monovalent hydrocarbon group free of conjugated aliphatic unsaturation; and R4 and R6 are independently hydrogen or a monovalent hydrocarbon group free of conjugated aliphatic unsaturation or together are an alkanediyl group, wherein the alkanediyl group and the carbon atoms to which it is attached form a carbocyclic ring having 4 to 7 carbon atoms; provided that R3 is not aryl. Methods of preparing the silacyclobutene compounds, silane polymers containing at least one silacyclobutene unit, and siloxane polymers containing at least one silacyclobutene unit.
Diastereoselective syn or anti opening of propargylic epoxides. Synthesis of α-allenic alcohols
Alexakis,Marek,Mangeney,Normant
, p. 1677 - 1696 (2007/10/02)
Propargylic epoxides easily react with Grignard reagents and catalytic amounts of copper(I) salt to afford α-allenic alcohols. The reaction is highly diastereoselective and its stereochemical outcome (syn or anti isomer) can be fully controlled. The syn d
Vinyl Cations, 37. Rearrangement of Cyclic Homopropargyl Sulfonates to Condensed Cyclobutanones and Cyclopropyl Ketones
Hanack, Michael,Schuhmacher, Werner,Kunzmann, Erich
, p. 1467 - 1487 (2007/10/02)
Cyclic homopropargyl sulfonates 8 (tosylates, triflates, nonaflates, and damsylates) are prepared and solvolysed.The resulting rearrangement reactions are studied with respect to the properties of the solvents used, leaving groups, the substituent on the triple bond, and with respect to the ring size of the sulfonates 8.
