32399-81-8Relevant academic research and scientific papers
Syntheses of 2-t-Alkylbuta-1,3-dienes and 2-Alkylthiobuta-1,3-dienes from 1,4-Dichlorobut-2-yne via Alkenylboranes
Hoshi, Masayuki,Masuda, Yuzuru,Arase, Akira
, p. 1629 - 1631 (1987)
2-t-Alkylbut-1,3-dienes were synthesized by the successive reaction of dialkylboranes, derived from tetrasubstituted ethenes and borane in tetrahydrofuran, with 1,4-dichlorobut-2-yne and methyl-lithium; 2-alkylthiobuta-1,3-dienes were synthesized by a sim
A New Synthesis of 2-Alkylbuta-1,3-dienes from Internal Alkenes and 1,4-Dichlorobut-2-yne via Dialkyl(1,4-dichlorobut-2-en-2-yl)boranes
Arase, Akia,Hoshi, Masayuki
, p. 531 - 532 (1987)
The successive treatment of borane in tetrahydrofuran with sterically-hindered internal alkenes, 1,4-dichlorobut-2-yne, and alkyl-lithium has provided good yields of 2-alkylbuta-1,3-dienes whose alkyl groups are derived from the alkene.
Crossed Regio- and Enantioselective Iron-Catalyzed [4+2]-Cycloadditions of Unactivated Dienes
Braconi, Elena,Cramer, Nicolai
, (2021/12/22)
The cyclohexene motif is ubiquitous in nature and specialty chemicals. A straightforward selective access to chiral cyclohexenes from unactivated dienes and dienophiles is not feasible by classical Diels–Alder reaction and constitutes an unsolved syntheti
A Cascade Suzuki-Miyaura/Diels-Alder Protocol: Exploring the Bifunctional Utility of Vinyl Bpin
Cain, David L.,McLaughlin, Calum,Molloy, John J.,Carpenter-Warren, Cameron,Anderson, Niall A.,Watson, Allan J. B.
, p. 787 - 791 (2019/04/25)
Cascade reactions are an important strategy in reaction design, allowing streamlining of chemical synthesis. Here we report a cascade Suzuki-Miyaura/Diels-Alder reaction, employing vinyl Bpin as a bifunctional reagent in two distinct roles: as an organoboron nucleo phile for cross-coupling and as a Diels-Alder dienophile. Merging these two reactions enables a rapid and operationally simple synthesis of functionalized carbocycles in good yield. The effect of the organoboron subtype on Diels-Alder regioselectivity was investigated and postsynthetic modifications were carried out on a model substrate. The potential for a complementary Heck/Diels-Alder process was also assessed.
Regio- and Diastereoselective Iron-Catalyzed [4+4]-Cycloaddition of 1,3-Dienes
Kennedy, C. Rose,Zhong, Hongyu,MacAulay, Rachel L.,Chirik, Paul J.
supporting information, p. 8557 - 8573 (2019/06/04)
A family of single-component iron precatalysts for the [4+4]-cyclodimerization and intermolecular cross-[4+4]-cycloaddition of monosubstituted 1,3-dienes is described. Cyclooctadiene products were obtained with high regioselectivity, and catalyst-controlled access to either cis- or trans-diastereomers was achieved using 4-substituted diene substrates. Reactions conducted either with single-component precatalysts or with iron dihalide complexes activated in situ proved compatible with common organic functional groups and were applied on multigram scale (up to >100 g). Catalytically relevant, S = 1 iron complexes bearing 2-(imino)pyridine ligands, (RPI)FeL2 (RPI = [2-(2,6-R2-C6H3-Na-CMe)-C5H4N] where R = iPr or Me, L2 = bis-olefin), were characterized by single-crystal X-ray diffraction, M??bauer spectroscopy, magnetic measurements, and DFT calculations. The structural and spectroscopic parameters are consistent with an electronic structure description comprised of a high spin iron(I) center (SFe = 3/2) engaged in antiferromagnetically coupling with a ligand radical anion (SPI = -1/2). Mechanistic studies conducted with these single-component precatalysts, including kinetic analyses, 12C/13C isotope effect measurements, and in situ M??bauer spectroscopy, support a mechanism involving oxidative cyclization of two dienes that determines regio- and diastereoselectivity. Topographic steric maps derived from crystallographic data provided insights into the basis for the catalyst control through stereoselective oxidative cyclization and subsequent, stereospecific allyl-isomerization and C-C bond-forming reductive elimination.
A General Nickel-Catalyzed Kumada Vinylation for the Preparation of 2-Substituted 1,3-Dienes
Fiorito, Daniele,Folliet, Sarah,Liu, Yangbin,Mazet, Clément
, p. 1392 - 1398 (2018/02/14)
The identification of two nickel(II) precatalysts for the preparation of 2-substituted 1,3-dienes by a Kumada cross-coupling between vinyl magnesium bromide and vinyl phosphates is described. This is noteworthy as engaging only one vinyl derivative in a transition-metal-catalyzed cross-coupling reaction is already reputedly challenging. Salient features of this method are its operational simplicity, the mild reaction conditions, the low catalyst loadings, the short reaction times, its scalability, and the use of stoichiometric quantities of each coupling partner. The tolerance of the two nickel catalysts to an important number of reactive functional groups and their compatibility with structurally complex molecular architectures has been extensively delineated. A Negishi variant of the reaction has been developed for even more sensitive organic functions such as ester or nitrile. Several other conjugated 1,3-dienes with various substitution patterns have been prepared by combining commercial alkenyl Grignard reagents and/or readily available alkenyl enol phosphates. Proper choice of the nickel catalyst and the reaction temperature gave access to a variety of different olefin isomers with high levels of stereocontrol. Overall, this approach affords conjugated dienes that would not be accessible otherwise and therefore provides a valuable complement to existing methods.
Enantioselective construction of all-carbon quaternary centers by branch-selective Pd-catalyzed allyl-allyl cross-coupling
Zhang, Ping,Le, Hai,Kyne, Robert E.,Morken, James P.
, p. 9716 - 9719 (2011/08/04)
The Pd-catalyzed cross-coupling of racemic tertiary allylic carbonates and allylboronates is described. This reaction generates all-carbon quaternary centers in a highly regioselective and enantioselective fashion. The outcome of these reactions is consistent with a process that proceeds by way of 3,3′-reductive elimination of bis(η1-allyl)palladium intermediates. Strategies for distinguishing the product alkenes and application to the synthesis of (+)-α-cuparenone are also described.
Iron-catalyzed 1,4-hydroboration of 1,3-dienes
Wu, Jessica Y.,Moreau, Benoit,Ritter, Tobias
supporting information; experimental part, p. 12915 - 12917 (2009/12/08)
(Chemical Equation Presented) A chemo-, regio-, and stereoselective iron-catalyzed 1,4-hydroboration of dienes that affords γ-disubstituted allylboranes has been developed. 1,4-Hydroboration of 2-substituted dienes forms allylborane products with (E)-trisubstituted double bonds exclusively.
All-carbon quaternary centers via ruthenium-catalyzed hydroxymethylation of 2-substituted butadienes mediated by formaldehyde: Beyond hydroformylation
Smejkal, Tomas,Han, Hoon,Breit, Bernhard,Krische, Michael J.
supporting information; experimental part, p. 10366 - 10367 (2009/12/08)
(Chemical Equation Presented) Ruthenium-catalyzed transfer hydrogenation of 2-substituted dienes 1a-i in the presence of paraformaldehyde results in reductive coupling at the 2-position to furnish the hydroxymethylation products 3a-i, which embody all-car
Synthesis of 2-Substituted Buta-1,3-dienes from 1,4-Dichlorobut-2-yne via Organoboranes
Hoshi, Masayuki,Arase, Akira
, p. 2693 - 2700 (2007/10/02)
The reaction of 1,4-dichlorobut-2-yne 1 with a stoichiometric amount of di-sec-alkylborane 2, prepared by the hydroboration of a sterically hindered anternal alkene with BH3 in tetrahydrofuran (THF), gave (Z)-(1,4-dichlorobut-2-en-2-yl)di-sec-alkylborane 3 stereospecifically.Treatment of compound 3 with methyllithium resulted in migration of an alkyl group from the boron atom to the adjacent carbon atom with elimination of two chlorine atoms to provide 2-sec-alkylbuta-1,3-dienes 5a-d.Similar treatment of (Z)-(1,4-dichlorobut-2-en-2-yl)-tert-alkyl-primary-alkylborane, prepared by the successive reaction of BH3 in THF with a tetrasubstituted ethene, relatively hindered terminal alkene, and compound 1, provided highly pure 2-tert-alkylbuta-1,3-dienes 5e and 5f whose alkyl group was derived from the tetrasubstituted alkene.On the other hand, similar treatment of compound 3, derived from a terminal or sterically unhindered unternal alkene by a modified hydroboration procedure, provided the corresponding 2-primary- (or 2-sec-)alkylbuta-1,3-dienes 5g-m. 2-(Alk-1-ynyl)buta-1,3-dienes 6a-c were provided by the successive reaction of dibromoborane-dimethylsulfide with compound 1, alk-1-ynyldiethylaluminium and methyllithium, although the yields were less good.Successive treatment of (Z)-(1,4-dichlorobut-2-en-2-yl)bis-(1,2-dimethylpropyl)borane 3b with alkylthiomagnesium bromide and methyllithium afforded exclusively 2-alkylthiobuta-1,3-dienes 8a-f whose alkylzhio group migrated from the boron atom via the borate complex.
