1236076-54-2Relevant academic research and scientific papers
Redox-Neutral Photocatalytic Cyclopropanation via Radical/Polar Crossover
Phelan, James P.,Lang, Simon B.,Compton, Jordan S.,Kelly, Christopher B.,Dykstra, Ryan,Gutierrez, Osvaldo,Molander, Gary A.
supporting information, p. 8037 - 8047 (2018/07/03)
A benchtop stable, bifunctional reagent for the redox-neutral cyclopropanation of olefins has been developed. Triethylammonium bis(catecholato)iodomethylsilicate can be readily prepared on multigram scale. Using this reagent in combination with an organic photocatalyst and visible light, cyclopropanation of an array of olefins, including trifluoromethyl- and pinacolatoboryl-substituted alkenes, can be accomplished in a matter of hours. The reaction is highly tolerant of traditionally reactive functional groups (carboxylic acids, basic heterocycles, alkyl halides, etc.) and permits the chemoselective cyclopropanation of polyolefinated compounds. Mechanistic interrogation revealed that the reaction proceeds via a rapid anionic 3-exo-tet ring closure, a pathway consistent with experimental and computational data.
Reductive Cyclopropanations Catalyzed by Dinuclear Nickel Complexes
Zhou, You-Yun,Uyeda, Christopher
supporting information, p. 3171 - 3175 (2016/03/12)
Dinuclear Ni complexes supported by naphthyridine-diimine (NDI) ligands catalyze the reductive cyclopropanation of alkenes with CH2Cl2 as the methylene source. The use of mild terminal reductants (Zn or Et2Zn) confers significant functional-group tolerance, and the catalyst accommodates structurally and electronically diverse alkenes. Mononickel catalysts bearing related N chelates afford comparatively low cyclopropane yields (≤20 %). These results constitute an entry into catalytic carbene transformations from oxidized methylene precursors.
Convenient access to various 1-cyclopropylcyclopropane derivatives
De Meijere, Armin,Khlebnikov, Alexander F.,Suennemann, Hans Wolf,Frank, Daniel,Rauch, Karsten,Yufit, Dmitrii S.
experimental part, p. 3295 - 3301 (2010/08/22)
1-Bromo-1-cyclopropylcyclopropane (1), which is easily accessible in two steps from methyl cyclopropanecarboxylate, does not form a stable Grignard reagent: upon reaction with elemental magnesium, yet it readily undergoes bromine/ lithium exchange without rearrangement upon treatment with tert-butyllithium in diethyl ether/pentane at -78 °C, and the resulting 1-lithio-1-cyclopropylcyclopropane can be trapped with various electrophiles to give the correspondingly 1-substituted bicyclopropyl derivatives 10 in yields ranging from 38 to over 90 % (13 examples). The (1-cyclopropylcyclopropyl) boronate 10m, which is also obtained from the 1-lithio derivative, has been subjected to Suzuki cross couplings with a number of aryl halides to furnish 1-aryl-1,1′bicyclopropyl compounds 11 (4 examples, 14-50% yield), predominantly without rearrangement. Further transformations of 1-cyclopropylcyclopropanecarbaldehyde (10e) have provided 2-(1- cyclopropylcyclopropyl)glycme (16), ethyl 3-(1-cyclopropylcyclopropyl)acrylate (17), and its cycloadducts with the nitrone 18 and cyclopentadiene 19, albeit the latter only in poor yield.
