386750-63-6Relevant academic research and scientific papers
Asymmetric Reductive and Alkynylative Heck Bicyclization of Enynes to Access Conformationally Restricted Aza[3.1.0]bicycles
Chi, Yonggui Robin,Huang, Xiaolei,Nguyen, Minh Hieu,Pu, Maoping,Wu, Yun-Dong,Zhang, Luoqiang,Zhou, Jianrong Steve
supporting information, p. 10814 - 10818 (2020/06/09)
Conformationally restricted azabicycles are becoming increasingly important in medicinal research. Asymmetric Heck bicyclization of enynes proceeds to give medicinally useful aza[3.1.0] and aza[4.1.0] bicycles with excellent enantioselectivity. The key organopalladium species after bicyclization can be trapped by silanes and terminal alkynes.
Hydrogenative Cyclopropanation and Hydrogenative Metathesis
Peil, Sebastian,Guthertz, Alexandre,Biberger, Tobias,Fürstner, Alois
supporting information, p. 8851 - 8856 (2019/05/28)
The unusual geminal hydrogenation of a propargyl alcohol derivative with [CpXRuCl] as the catalyst entails formation of pianostool ruthenium carbenes in the first place; these reactive intermediates can be intercepted with tethered alkenes to give either cyclopropanes or cyclic olefins as the result of a formal metathesis event. The course of the reaction is critically dependent on the substitution pattern of the alkene trap.
Enantioselective Intramolecular C?H Insertion of Donor and Donor/Donor Carbenes by a Nondiazo Approach
Zhu, Dong,Ma, Jun,Luo, Kui,Fu, Hongguang,Zhang, Li,Zhu, Shifa
supporting information, p. 8452 - 8456 (2016/07/19)
The first enantioselective intramolecular C?H insertion and cyclopropanation reactions of donor- and donor/donor-carbenes by a nondiazo approach are reported. The reactions were conducted in a one-pot manner without slow addition and provided the desired
Au-catalyzed piperidine synthesis via tandem acyloxy migration/ intramolecular [3 + 2] cycloaddition of enynyl esters
Zheng, Huaiji,Huo, Xing,Zhao, Changgui,Jing, Peng,Yang, Juan,Fang, Bowen,She, Xuegong
, p. 6448 - 6451 (2012/02/03)
An Au-catalyzed tandem protocol involving enynyl ester isomerization and subsequent intramolecular [3 + 2] cyclization has been developed. This strategy provides an efficient approach for the synthesis of polyfunctional piperidines, which are subunits of
Phenylsulfonyl ene-allenes as efficient precursors to bicyclic systems via intramolecular [2 + 2]-cycloaddition reactions
Padwa, Albert,Lipka, Helmut,Watterson, Scott H.,Murphree, S. Shaun
, p. 6238 - 6250 (2007/10/03)
Various phenylsulfonyl allene derivatives were prepared with double bonds tethered either to the α-position or the γ-position of the allene. These substrates underwent a highly regio- and stereospecific thermal [2 + 2]-cycloaddition across the nonactivated cumulene double bond, forming distal cycloadducts (i.e., 57) in the case of α-tethered allenes and proximal adducts (i.e., 25) in the case of γ-tethered allenes. The mechanistic rationale for the observed stereospecificity involves initial diradical formation, followed by a rapid ring closure to the more stable cis-fused ring system. The tether may be equipped with heteroatoms, allowing for the formation of fused heterocycles (e.g., 61), and the cycloaddition can be facilitated by the introduction of sterically bulky groups and/or by conformational rigidity to the tether. Other modes of cyclization were observed in the presence of sodium benzenesulfinate or Lewis acids, in which cases polar mechanisms prevail. The chemoselectivity is reversed for [4 + 2]-cycloadditions, which prefer instead to engage the vinyl sulfone moiety, independent of whether the tether is attached to the α- or γ-position of the allene.
Synthesis of bicyclic pyrane derivatives via tungsten-mediated [3 + 3] cycloaddition of epoxides with tethered alkynes
Shen, Kuo-Hui,Lush, Shie-Fu,Chen, Tseng-Li,Liu, Rai-Shung
, p. 8106 - 8111 (2007/10/03)
Propargyltungsten compounds bearing a tethered epoxide were prepared in short steps from readily available materials. In the presence of various Lewis acids, BF3·Et2O catalysts (25 mol %) most effectively promote the [3 + 3] cycloaddition of the epoxide with its tethered propargyltungsten group, delivering bicyclic pyranyltungsten compounds in reasonable yields. This cyclization proceeds highly diastereoselectively with tolerance of various functional groups. The stereochemical outcome indicates that the cycloaddition is initiated by the ring opening of the epoxides via an exo-attack of the propargyltungsten group. The resulting pyranyltungsten organometallics were demetalated to yield various bicyclic pyranyl derivatives using different oxidants. This new method provides a short enantiospecific synthesis of bicyclic oxygen compounds if chiral epoxide is used in the cyclizatlon. A mechanistic model is presented to rationalize the reaction pathway of this [3 + 3] cycloaddition.
