75101-99-4Relevant articles and documents
Synthesis of highly functionalized [3]dendralenes and their Diels-Alder reactions displaying unexpected regioselectivity
Naidu, Gonna Somu,Singh, Rekha,Kumar, Mukesh,Ghosh, Sunil K.
, p. 37136 - 37148 (2016)
Acyclic tetrasubstituted [3]dendralenes stable towards D-A cyclodimerization were prepared by the double olefination of substituted dienyl phosphonates with dimethylsulfonium methylide, followed by H-W-E olefination of the formed butadienylphosphonoacetates with aldehydes. The X-ray structure of a [3]dendralene with a 4-position benzyl substitution revealed that an electron-rich diene exists in the s-trans conformation, leading to the stability. This structural preference of dendralenes leads to an unusual regioselectivity in the D-A reaction, wherein a deactivated diene participated in the process and displayed endo selectivity. The steric bulk of the groups at the 2 and 4 positions govern the regioselectivity and dominates the electronic effects. For the dendralenes possessing a 4-methyl substituent, the electronically rich diene participated in the D-A reaction. These D-A adducts failed to undergo further cycloaddition owing to steric crowding, which resulted in gauche conformation of the diene, as evidenced by X-ray structures of the adducts.
Complex Polyheterocycles and the Stereochemical Reassignment of Pileamartine A via Aza-Heck Triggered Aryl C-H Functionalization Cascades
Bower, John F.,Caiger, Lewis,García-Cárceles, Javier,Hazelden, Ian R.,Jones, Benjamin T.,Langer, Thomas,Lewis, Richard J.
supporting information, p. 15593 - 15598 (2021/10/12)
Structurally complex benzo- and spiro-fused N-polyheterocycles can be accessed via intramolecular Pd(0)-catalyzed alkene 1,2-aminoarylation reactions. The method uses N-(pentafluorobenzoyloxy)carbamates as the initiating motif, and this allows aza-Heck-type alkene amino-palladation in advance of C-H palladation of the aromatic component. The chemistry is showcased in the first total synthesis of the complex alkaloid (+)-pileamartine A, which has resulted in the reassignment of its absolute stereochemistry.
Asymmetric Nazarov Cyclizations of Unactivated Dienones by Hydrogen-Bond-Donor/Lewis Acid Co–Catalyzed, Enantioselective Proton-Transfer
Metternich, Jan B.,Reiterer, Martin,Jacobsen, Eric N.
, p. 4092 - 4097 (2020/09/01)
We report an enantioselective Nazarov cyclization catalyzed by chiral hydrogen-bond-donors in concert with silyl Lewis acids. The developed transformation provides access to tri-substituted cyclopentenones in high levels of enantioselectivity (up to 95% e.e.) from a variety of simple unactivated dienones. Kinetic and mechanistic studies are consistent with a reversible 4π-electrocyclization C?C bond-forming step followed by rate- and enantio-determining proton-transfer as the mode of catalysis. (Figure presented.).
Dehydrogenative β-Arylation of Saturated Aldehydes Using Transient Directing Groups
Zhang, Xing-Long,Pan, Gao-Fei,Zhu, Xue-Qing,Guo, Rui-Li,Gao, Ya-Ru,Wang, Yong-Qiang
supporting information, p. 2731 - 2735 (2019/04/30)
An unprecedented cross-dehydrogenative-coupling (CDC) reaction of saturated aldehyde β-C-H with arenes to form cinnamaldehydes via the cleavages of four C-H bonds has been developed. The reaction possesses complete E-stereoselectivity for the C=C double bond. The protocol is featured by atom and step economy, mild reaction conditions, and convenient operation.
Enantioselective Nazarov Cyclizations Catalyzed by an Axial Chiral C6F5-Substituted Boron Lewis Acid
Süsse, Lars,Vogler, Maria,Mewald, Marius,Kemper, Benedict,Irran, Elisabeth,Oestreich, Martin
supporting information, p. 11441 - 11444 (2018/08/28)
A chiral variant of B(C6F5)3 with a 3,3′-disubstituted binaphthyl backbone is shown to catalyze Nazarov cyclizations with high levels of enantio- and diastereocontrol. The parent B(C6F5)3 a
Assembly of indenamine derivatives through in situ formed N-sulfonyliminium ion initiated cyclization
Fan, Xiaohui,Lv, Hao,Guan, Yong-Hong,Zhu, Hong-Bo,Cui, Xiao-Meng,Guo, Kun
supporting information, p. 4119 - 4122 (2014/04/03)
An expedient route to structurally diverse indenamine derivatives through condensation of the readily accessible substituted cinnamylaldehydes and sulfonylamines under the catalysis of FeCl3 has been developed, featuring high efficiency in the generation of two bonds and one ring in a single-step and water as the only by-product. This journal is the Partner Organisations 2014.
Selective reactivity of electron-rich aryl iodides in the Heck arylation of disubstituted alkenes catalyzed by palladium-arylurea complexes
Smith, Matthew R.,Jang, Young Jin,Kim, Jung Yun,Ciufolini, Marco A.
, p. 10139 - 10151 (2013/11/06)
A catalyst consisting of 1 mol % of the 1:2 complex of Pd(OAc)2 with N-(4-carbethoxyphenyl)urea promotes the Heck arylation of 2- or 3-substituted, conjugated esters, nitriles, aldehydes, and ketones (an uncharacteristically broad range of substrates), but only with electron-rich aryl iodides (an uncharacteristically narrow range of halides).
Neutral nazarov-type cyclization catalyzed by palladium(0)
Shimada, Naoyuki,Stewart, Craig,Bow, William F.,Jolit, Anais,Wong, Kahoano,Zhou, Zhe,Tius, Marcus A.
supporting information; experimental part, p. 5727 - 5729 (2012/08/07)
Joining the circle: The first Pd0 catalyzed Nazarov-type cyclization of diketoesters (see scheme) proceeds in 70 % to 95 % yield under strictly neutral pH conditions. Aryl substitution of the diketoesters is not required, so the reaction shows great versatility and can also proceed with aliphatic substrates. Copyright
An organocatalytic asymmetric nazarov cyclization
Basak, Ashok K.,Shimada, Naoyuki,Bow, William F.,Vicic, David A.,Tius, Marcus A.
supporting information; experimental part, p. 8266 - 8267 (2010/08/04)
An organocatalytic asymmetric Nazarov cyclization of diketoesters that proceeds by means of a dual activation mechanism has been developed. Screening of a number of catalysts led to a new thiourea that incorporates a primary amino group. The method gives rise to cyclic products with two adjacent quaternary asymmetric carbon atoms, one of which is an all-carbon stereocenter, with complete or nearly complete diastereoselectivity and in high or very high enantiomeric excess. A brief and very convenient synthesis of the acyclic diketoester starting materials through nucleophilic addition to a ketene is also described.
Traceless sulfone linker cleavage triggered by ozonolysis: solid-phase synthesis of diverse α-β-unsaturated carbonyl compounds
Chang, Yi-Fan,Jiang, Yi-Rui,Cheng, Wei-Chieh
, p. 543 - 547 (2008/04/13)
The highly efficient and convenient protocol to prepare diverse α,β-unsaturated aldehydes, ketones, and acids via the parallel solid-phase synthesis is developed. The key sulfone linker cleavage strategy is performed by ozonolysis to generate a carbonyl moiety followed by base-mediated polymer-bound sulfinate elimination to release our desired molecules from the resin. All α,β-unsaturated carbonyl compounds are prepared in good purities and yields without further purification.
