3899-20-5Relevant articles and documents
Iron-Catalyzed Vinylzincation of Terminal Alkynes
Huang, Qiang,Su, Yu-Xuan,Sun, Wei,Hu, Meng-Yang,Wang, Wei-Na,Zhu, Shou-Fei
, p. 515 - 526 (2022/01/08)
Organozinc reagents are among the most commonly used organometallic reagents in modern synthetic chemistry, and multifunctionalized organozinc reagents can be synthesized from structurally simple, readily available ones by means of alkyne carbozincation. However, this method suffers from poor tolerance for terminal alkynes, and transformation of the newly introduced organic groups is difficult, which limits its applications. Herein, we report a method for vinylzincation of terminal alkynes catalyzed by newly developed iron catalysts bearing 1,10-phenanthroline-imine ligands. This method provides efficient access to novel organozinc reagents with a diverse array of structures and functional groups from readily available vinylzinc reagents and terminal alkynes. The method features excellent functional group tolerance (tolerated functional groups include amino, amide, cyano, ester, hydroxyl, sulfonyl, acetal, phosphono, pyridyl), a good substrate scope (suitable terminal alkynes include aryl, alkenyl, and alkyl acetylenes bearing various functional groups), and high chemoselectivity, regioselectivity, and stereoselectivity. The method could significantly improve the synthetic efficiency of various important bioactive molecules, including vitamin A. Mechanistic studies indicate that the new iron-1,10-phenanthroline-imine catalysts developed in this study have an extremely crowded reaction pocket, which promotes efficient transfer of the vinyl group to the alkynes, disfavors substitution reactions between the zinc reagent and the terminal C–H bond of the alkynes, and prevents the further reactions of the products. Our findings show that iron catalysts can be superior to other metal catalysts in terms of activity, chemoselectivity, regioselectivity, and stereoselectivity when suitable ligands are used.
Synthesis of dienyl ketones via palladium(II)-catalyzed direct cross-coupling reactions between simple alkenes and vinyl ketones: Application to the synthesis of vitamin a1 and bornelone
Zhang, Xiang,Wang, Min,Zhang, Ming-Xin,Xu, Yun-He,Loh, Teck-Peng
, p. 5531 - 5533 (2013/11/19)
An efficient and general method for the synthesis of conjugated dienyl ketones via palladium(II) acetate catalyzed direct cross-coupling between simple alkenes and vinyl ketones is reported. This method has been successfully applied for the synthesis of V
A cross-metathesis approach to the synthesis of new etretinate type retinoids, ethyl retinoate and its 9Z-isomer
Maj, Jadwiga,Morzycki, Jacek W.,Rárová, Lucie,Wasilewski, Grzegorz,Wojtkielewicz, Agnieszka
, p. 5430 - 5433 (2012/11/07)
Two aromatic retinoids were synthesized from styrene derivatives using a novel strategy with a cross-metathesis reaction as a key step. The biological activity of the new etretinate analogues was tested. Cross-metathesis reactions were also employed for the preparation of ethyl retinoate and its 9Z-isomer via the C15 + C5 route.
Cross metathesis approach to retinoids and other β-apocarotenoids
Wojtkielewicz, Agnieszka,Maj, Jadwiga,Dzieszkowska, Agnieszka,Morzycki, Jacek Witold
supporting information; experimental part, p. 6868 - 6875 (2011/10/02)
Cross metathesis (CM) reactions between polyenes, such as β-carotene, canthaxanthin or retinyl acetate, and various alkenes or dienes in the presence of second generation Hoveyda-Grubbs (H II) or Grubbs (G II) catalysts were investigated. Depending on the
Cross metathesis of β-carotene with electron-deficient dienes. A direct route to retinoids
Wojtkielewicz, Agnieszka,Maj, Jadwiga,Morzycki, Jacek W.
supporting information; experimental part, p. 4734 - 4737 (2011/03/18)
Cross metathesis (CM) reactions of β-carotene and alkenes occur regioselectively in the presence of the Hoveyda second generation catalyst. Scission of the C15-C15′ and C11-C12 bonds of β-carotene in all CM reactions predominates. The reaction with ethyl
Preparation and biological activity of 13-substituted retinoic acids
Wada, Akimori,Fukunaga, Kouki,Ito, Masayoshi,Mizuguchi, Yukari,Nakagawa, Kimie,Okano, Toshio
, p. 3931 - 3942 (2007/10/03)
13-Demethyl or 13-substituted all-E- and 9Z-retinoic acids were synthesized using a palladium-catalyzed coupling reaction of enol triflates and tributylstannylolefins. Their biological activities were then measured. The 13-ethyl analogs exhibited approximately one-half of the antiproliferative and differentiation-inducing activity of ATRA in HL-60 cells. In contrast, in the 9Z-derivatives, all analogs, except for the 13-butyl derivatives, showed apoptosis-inducing activity.
Stereocontrolled synthesis of 13-substituted retinoic acids by palladium-catalyzed coupling reaction of alkenyl stannane with vinyl triflate
Wada,Fukunaga,Ito
, p. 800 - 802 (2007/10/03)
A novel method for the stereoselective synthesis of all-E-, 13Z- and 9Z- retionic acid esters was developed by palladium-catalyzed cross coupling reactions of tetraenyl stannanes with E- or Z-vinyl triflates in good yields. Applying this methodology, 13-substituted all-E- and 9Z- retinoic acids were prepared in satisfactory yields.
A comprehensive survey of Stille-type C(sp2)-C(sp2) single bond forming processes in the synthesis of retinoic acid and analogs
Dominguez, Beatriz,Iglesias, Beatriz,De Lera, Angel R.
, p. 15071 - 15098 (2007/10/03)
The synthesis of the retinoid skeleton has been exhaustively explored using the Stille coupling for the formation of the side- chain single bonds. On employing the experimental catalytic conditions developed by Farina [Pd2(dba)3, AsPh3, NMP] we have modified the electronic and steric requirement of the coupling partners, alkenyl stannanes and electrophiles (alkenyl iodides and triflates). The comprehensive survey afforded appropriately matched components for every bond formation considered. Moreover, from the comparison of the reactivities of different coupling partners with different degrees of steric hindrance, the sensitivity of the Stille coupling to steric effects was confirmed. Besides providing a variety of building blocks for retinoid synthesis, the study highlights some trends that might be useful for the application of the Stille reaction to the synthesis of unsubstituted conjugated polyenes.
Stereoselective synthesis of 9-cis-retinoic acid by Suzuki reaction
Pazos, Yolanda,De Lera, Angel R.
, p. 8287 - 8290 (2007/10/03)
The entire polyenic side chain of ethyl 9-cis-retinoate (7) has been stereoselectively synthesized and attached to the hydrophobic ring by a high-yielding thallium-accelerated Suzuki cross-coupling reaction. The Suzuki reaction partners, tetraenyl iodide 18 and alkenyl organoborane 19, are more conveniently used immediately after generation from their precursors. Alternative approaches using either the Stille reaction or a Suzuki reaction with a shorter polyenic component proved less efficient. The highly convergent sequence can be adapted to the preparation of analogs of 9-cis-retinoic acid (2), the natural ligand for the retinoid X (RXR) subfamily of nuclear receptors.
