727975-12-4Relevant academic research and scientific papers
Enantioselective Rh(II)-Catalyzed Desymmetric Cycloisomerization of Diynes: Constructing Furan-Fused Dihydropiperidines with an Alkyne-Substituted Aza-Quaternary Stereocenter
Cao, Tongxiang,Chen, Kai,Lu, Jiajun,Ma, Jun,Wu, Rui,Zhu, Shifa
, p. 14916 - 14925 (2021/09/18)
Described herein is an enantioselective dirhodium(II)-catalyzed cycloisomerization of diynes achieved by the strategy of desymmetrization, which not only represents a new cycloisomerization reaction of diynes but also constitutes the first Rh(II)-catalyzed asymmetric intramolecular cycloisomerization of 1,6-diynes. This protocol provides a range of valuable furan-fused dihydropiperidine derivatives with an enantiomerically enriched alkynyl-substituted aza-quaternary stereocenter in high efficiency, complete atom economy, and excellent enantioselectivity (up to 98% ee). Besides, the highly functionalized products could be easily transformed into various synthetically useful building blocks and conjugated with a series of pharmaceutical molecules. The mechanism involving a concerted [3+2] cycloaddition/[1,2]-H shift of the Rh(II) carbenoid intermediate was elucidated by DFT calculations and mechanistic studies. More importantly, the first single crystal of alkyne-dirhodium(II) was obtained to show that a η2-coordinating activation of alkynal by dirhodium(II) was involved. Weak hydrogen bondings between the carboxylate ligands and alkynal were found, which probably made the well-defined paddlewheel-like dirhodium(II) distinctive from other metal complexes in catalyzing this transformation. Furthermore, the origin of the enantioselectivity was elucidated by a Rh2(R-PTAD)4-alkyne complex and additional calculational studies.
Gold(I)-Catalyzed Cascade Cyclization Reactions of Allenynes for the Synthesis of Fused Cyclopropanes and Acenaphthenes
Ikeuchi, Takaya,Inuki, Shinsuke,Oishi, Shinya,Ohno, Hiroaki
, p. 7792 - 7796 (2019/05/15)
A gold-catalyzed reaction of phenylene-tethered allenynes with benzofurans gave 1-(naphth-1-yl)cyclopropa[b]benzofuran derivatives, whereas the reaction of 1-allenyl-2-ethynyl-3-methylbenzene derivatives in the absence of benzofurans gave acenaphthenes in good yields. These results can be rationalized by nucleophilic attack of the alkyne moiety on an activated allene to form a vinyl cation intermediate.
Synthesis of [1,2,3]Triazolo[5,1- a]isoquinoline Derivatives via a Selective Cascade Cyclization Sequence of 1,2-bis(Phenylethynyl)benzene Derivatives
Tao, Shipeng,Hu, Qinquan,Li, Huan,Ma, Shan,Chen, Yunfeng
supporting information, p. 1354 - 1361 (2015/05/19)
(Graphical Presented). A direct, concise, synthetic method for the generation of [1,2,3]triazolo[5,1-a]isoquinoline derivatives, using a selective cascade cyclization of unsymmetrical substituted 1,2-bis(phenylethynyl)benzene derivatives with NaN3, has been developed. The reaction gave different substituted [1,2,3]triazolo[5,1-a]isoquinolines in moderate to good yields. It was found that the substituents on the alkynes were important for the selectivities of the cascade cyclization sequences.
Synthesis of tetracyclic chromenones via platinum(ii) chloride catalysed cascade cyclization of enediyne-enones
Sivaraman, Mahalingam,Perumal, Paramasivan T.
, p. 1318 - 1327 (2014/03/21)
PtCl2 catalysed cascade cyclization of an enediyne-enone system to afford a tetracyclic chromenone is reported, which proceeds through two consecutive highly regioselective 6-endo-dig cyclizations in a single step with the formation of two new C-C bonds and two new rings in excellent yield. A mechanism for this transformation is proposed based on the isolated intermediates.
Synthesis of indeno-fused derivatives of quinolizinium salts, imidazo[1,2-a]pyridine, pyrido[1,2-a]indole, and 4H-quinolizin-4-one via benzannulated enyne-allenes
Dai, Weixiang,Petersen, Jeffrey L.,Wang, Kung K.
, p. 6647 - 6652 (2007/10/03)
The benzannulated enediynyl propargylic alcohol 8 was prepared from 1-bromo-2-iodobenzene by two consecutive Sonogashira cross-coupling reactions. The subsequent transformation to mesylate 9 followed by treatment with 4-substituted pyridines 10 then furni
