Branched Amine Synthesis via Aziridine or Azetidine Opening with Organotrifluoroborates by Cooperative Brønsted/Lewis Acid Catalysis: An Acid-Dependent Divergent Mechanism
作者:Truong N. Nguyen、Jeremy A. May
DOI:10.1021/acs.orglett.8b01394
日期:2018.6.15
A practical catalytic method to synthesize β,β- and γ,γ-substituted amines by opening aziridines and azetidines, respectively, using alkenyl, alkynyl, or aryl/heteroaryl trifluoroborate salts is described. This reaction features simple open-flask reaction conditions, the use of transition-metal-free catalysis, complete regioselectivity, and high diastereoselectivity. Preliminary mechanistic studies
designed a series of hydroxy(aryl)‐λ3‐iodane–[18]crown‐6 complexes, prepared from the corresponding iodosylbenzene derivatives and superacids in the presence of [18]crown‐6, and have investigated their reactivities in aqueous media. These activated iodosylbenzene monomers are all non‐hygroscopic shelf‐storable reagents, but they maintain high oxidizing ability in water. The complexes are effective for
Brønsted Acid Catalyzed Homoconjugate Addition of Organotrifluoroborates to Arylated Cyclopropyl Ketones
作者:Truong N. Nguyen、Thien S. Nguyen、Jeremy A. May
DOI:10.1021/acs.orglett.6b01795
日期:2016.8.5
A novel and practical homoconjugate addition of alkenyl, alkynyl, heteroaryl, and aryl trifluoroborates to arylated cyclopropylketones to synthesize γ,γ-disubstituted ketones is reported. A preliminary mechanistic proposal involving ketone protonation, an intermediary carbocation, and intermolecular nucleophile addition has been made based on control studies.
A Mild and Regiospecific Synthesis of Pyrazoleboranes
作者:Andrew W. Brown、Júlia Comas-Barceló、Joseph P. A. Harrity
DOI:10.1002/chem.201701019
日期:2017.4.19
Alkynylboranes show unprecedented reactivity in their [4+2] cycloaddition of sydnones offering access to fully substituted pyrazoles within a few hours at room temperature. This method delivers synthetically valuable pyrazoleboranes with complete control of regioselectivity, and these intermediates can be further elaborated through functionalization of the C−B bond.