6050-01-7Relevant academic research and scientific papers
NiH-Catalyzed Proximal-Selective Hydroamination of Unactivated Alkenes
Jeon, Jinwon,Lee, Changseok,Seo, Huiyeong,Hong, Sungwoo
, p. 20470 - 20480 (2020/11/27)
Reported herein is a modular, NiH-catalyzed system capable of proximal-selective hydroamination of unactivated alkenes with diverse amine sources. The key to the successful implementation of this approach is the promotion of NiH insertion into even highly substituted olefins via coordination of the bidentate directing group to the nickel complex. A wide range of primary and secondary amines can be installed in both internal and terminal unactivated alkenes with excellent regiocontrol under the optimized reaction conditions. This protocol is flexible and general for the preparation of a variety of valuable β- and γ-amino acid building blocks that would otherwise be difficult to synthesize. The utility of this transformation was further demonstrated by the site-selective late-stage modification of complex and medicinally relevant molecules. Combined experimental and computational studies illuminate the detailed reaction mechanism.
Intermolecular Heck Coupling with Hindered Alkenes Directed by Potassium Carboxylates
Huffman, Tucker R.,Wu, Yebin,Emmerich, Alexis,Shenvi, Ryan A.
supporting information, p. 2371 - 2376 (2019/02/03)
Pd0-catalyzed Mizoroki–Heck reactions traditionally exhibit poor reactivity with polysubstituted, unbiased alkenes. Intermolecular reactions with simple, all-carbon tetrasubstituted alkenes are unprecedented. Herein we report that pendant carboxylic acids, combined with bulky monophospine ligands on palladium, can direct the arylation of tri- and tetrasubstituted olefins. Quaternary carbons are established at high Fsp3 attached-ring junctures and the carboxylate directing group can be removed after coupling. Carboxylate directivity prevents over-arylation of the new, less substituted alkene, which can be diversified in subsequent reactions.
Photo-Organocatalytic Enantioselective Radical Cascade Reactions of Unactivated Olefins
Bonilla, Pablo,Rey, Yannick P.,Holden, Catherine M.,Melchiorre, Paolo
supporting information, p. 12819 - 12823 (2018/09/20)
Radical cascade processes are invaluable for their ability to rapidly construct complex chiral molecules from simple substrates. However, implementing catalytic asymmetric variants is difficult. Reported herein is a visible-light-mediated organocatalytic strategy that exploits the excited-state reactivity of chiral iminium ions to trigger radical cascade reactions with high enantioselectivity. By combining two sequential radical-based bond-forming events, the method converts unactivated olefins and α,β-unsaturated aldehydes into chiral adducts in a single step. The implementation of an asymmetric three-component radical cascade further demonstrates the complexity-generating power of this photochemical strategy.
One-pot regio- and stereoselective cyclization of 1,2,n-triols
Zheng, Tao,Narayan, Radha S.,Schomaker, Jennifer M.,Borhan, Babak
, p. 6946 - 6947 (2007/10/03)
A simple and efficient process to cyclize triols containing a 1,2-diol functionality with a pendant hydroxyl group is presented. The one-pot procedure converts the 1,2-diol into an ortho ester in situ, which upon treatment with a Lewis acid generates a cyclic acetoxonium intermediate. This intermediate is subsequently trapped by the pendant hydroxyl group to generate a cyclic ether. The stereochemistry of the 1,2-diol is transferred to the product with complete fidelity (inversion at the site of cyclization), and the reaction proceeds with high regioselectivity. The process is akin to the Lewis acid-catalyzed intramolecular ring-opening of epoxides with hydroxyl groups yielding cyclic ethers of various sizes with regio- and stereochemical control. Copyright
