21964-44-3Relevant articles and documents
Radical reactions of epoxy esters induced by titanocene chloride
Fernández-Mateos,Herrero Teijón,Rabanedo Clemente,Rubio González
, p. 7755 - 7758 (2006)
The reductive radical cyclizations of several epoxy esters have been achieved using titanocene chloride. The tether length from the initial radical to the carbonyl acceptor is the key of the reactions. We obtained products from radical cyclization onto carbonyl formate and products from formate and hydrogen elimination. The stereochemical outcome of the 5-exo radical cyclization of two diastereomers is reported. A radical cascade cyclization of an unsaturated epoxy formate is also described.
Annulation-retro-Claisen cascade of bifunctional peroxides for the synthesis of lactone natural products
Hu, Lin,Li, Jialin,Li, Xuemin,Xu, Qianlan
supporting information, p. 274 - 277 (2022/01/03)
A new and highly efficient annulation-retro-Claisen cascade, which involves the [4 + 1] or [5 + 1] annulation of α-benzoylacetates with bielectrophilic peroxides and a subsequent debenzoylation process under mild basic conditions, has been developed for the rapid construction of valuable tetrahydrofuran- and dihydropyran-2-carboxylates in good yields. By employing the new reaction, the unified total synthesis of γ- and δ-lactone natural products such as (±)-tanikolide, (±)-goniothalamins, (±)-7-epi-goniodiol, and (±)-plakolide A has been accomplished in 4-7 steps.
β-Borylation of conjugated carbonyl compounds with silylborane or bis(pinacolato)diboron catalyzed by Au nanoparticles
Fragkiadakis, Michael,Kidonakis, Marios,Stratakis, Manolis
supporting information, p. 8921 - 8927 (2020/11/23)
Conjugated aldehydes and ketones undergo reaction with Me2PhSiBpin (pin: pinacolato) catalyzed by Au nanoparticles supported on TiO2 forming exclusively the β-borylation products, via the intermediate formation of the labile silaboration adducts. This chemoselectivity pathway is complementary to the so far known analogous reaction catalyzed by other metals, where β-silylation occurs instead. β-Borylation also occurs with pinBBpin under identical reaction conditions in a variety of conjugated carbonyl compounds, including esters and amides which are unreactive in their attempted Au-catalyzed silaboration. This journal is
Silica-coated Fe3O4 magnetic nanoparticles-supported sulfonic acid as a highly active and reusable catalyst in chemoselective deprotection of tert-butyldimethylsilyl (TBDMS) ethers
Hossein Javadi, Sayed,Zareyee, Daryoush,Monfared, Azam,Didehban, Khadijeh,Mirshokraee, Sayed Ahmmad
supporting information, p. 7 - 12 (2019/11/03)
Anchored propyl sulfonic acid on the surface of silica-coated magnetic nanoparticles (Fe3O4@SiO2@PrSO3H) was successfully employed in the deprotection of TBDMS ethers. The prepared magnetically separable nanocatalyst exhibited efficient catalytic activity with high conversion and selectivity in cleavage of TBDMS ethers. TBDMS ethers are efficiently cleaved to the corresponding hydroxyl compounds in methanol solution containing 2 mol% magnetic nano-catalysts. Good to excellent yields of products, simple work-up and product separation, selective cleavage of TBDMS ethers in the presence of TBDPS ethers, easy recycling of the catalyst with external magnet with no loss in its activity (7 reaction cycles) are important features of this new protocol.
Ruthenium-Catalyzed Direct Dehydrogenative Cross-Coupling of Allyl Alcohols and Acrylates: Application to Total Synthesis of Hydroxy β-Sanshool, ZP-Amide I, and Chondrillin
Dethe, Dattatraya H.,Nagabhushana, C. B.
supporting information, (2020/02/15)
Ru-catalyzed oxidative coupling of allyl alcohols and activated olefins has been developed by C(allyl)-H activation of allyl alcohols providing efficient and direct access to synthetically useful α,β-unsaturated enone intermediates. Synthetic utility of this method was demonstrated by its application to synthesis of bioactive natural products such as Hydroxy-β-sanshool, ZP-amide I, Chondrillin, Plakorin, and (+)-cis-Solamin A.
Enantioselective addition of selenosulfonates to α,β-unsaturated ketones
Luo, Shilong,Zhang, Nan,Wang, Zhen,Yan, Hailong
supporting information, p. 2893 - 2901 (2018/05/03)
An organo-catalyzed enantioselective addition of selenosulfonates to α,β-unsaturated ketones was developed for the first time. With a chiral squaramide as an efficient catalyst, the desired α-selenylated ketones were obtained in a good yields with high enantioselectivity up to 89% ee, and good results could be obtained on a gram scale. The products could also be efficiently transformed into useful building blocks with a propenylic stereocenter; the strategy presented in this study may find further applications in organic synthesis.
Iron-Catalyzed Grignard Cross-Couplings with Allylic Methyl Ethers or Allylic Trimethylsilyl Ethers
Seto, Chika,Otsuka, Takeshi,Takeuchi, Yoshiki,Tabuchi, Daichi,Nagano, Takashi
supporting information, p. 1211 - 1214 (2018/03/26)
We have found that cross-coupling between aryl Grignard reagents and allylic methyl ethers proceeded well in the presence of a catalytic amounts of Fe(acac) 3 to afford the corresponding allylic substitution products in good yields. Under the same conditions, allylic trimethylsilyl ethers also reacted with Grignard reagents to give the corresponding cross-coupling products.
One-Pot Transformation of Simple Furans into Octahydroindole Scaffolds
Kalaitzakis, Dimitris,Triantafyllakis, Myron,Ioannou, Georgios I.,Vassilikogiannakis, Georgios
supporting information, p. 4020 - 4023 (2017/03/27)
A highly efficient and general singlet-oxygen-initiated one-pot transformation of readily accessible furans into octahydroindole scaffolds has been developed.
Highly efficient kinetic resolution of allylic alcohols with terminal double bond
Marques, Francisco A.,Oliveira, Marcos A.,Frensch, Gustavo,Sales Maia, Beatriz Helena L. N.,Barison, Andersson,Lenz, Cesar A.,Guerrero Jr., Palimecio G.
experimental part, p. 696 - 700 (2012/06/04)
In this study, the lipase-catalyzed kinetic resolution (Novozyme 435) was employed to prepare chiral allylic alcohols and acetates with terminal double bonds in enantiomeric excesses ranging from 94 to >99 %.
Titanocene-promoted eliminations on epoxy alcohols and epoxy esters
Fernandez-Mateos, Alfonso,Madrazo, Soledad Encinas,Teijon, Pablo Herrero,Gonzalez, Rosa Rubio
experimental part, p. 856 - 861 (2010/04/05)
The reaction of a series of 2,3-epoxy alcohols and the corresponding formates, acetates, and benzoates promoted by Cp2TiCl has been studied. The different outcome of the reaction of epoxy derivatives has been rationalized in terms of mechanistically biased processes. After homolytic oxirane cleavage, four main types of reaction were found: dehydroxylation, decarboxylation, dehydrogenation, and deoxygenation. The reaction products varied according to the substitution pattern. The radical nature of these eliminations is demonstrated.
