Gold‐Catalyzed Intermolecular Hydroamination of Allenes with Arylamines and Resulting High Chirality Transfer

Abstract

Hydroamination, the formal addition of an N À H bond across a CÀC unsaturated bond, is a highly desirable and atomeconomical process for the preparation of amine derivatives.[1] It is known that hydroamination of alkenes and alkynes can be catalyzed by 1) organolanthanides, [2] 2) alkali metals, [3] 3) early (Ti, Zr) [4] and 4) late (Pd, Rh, Ru, Ir, Ni, Au) [5] transition metals, and 5) heterogeneous systems.[6]Depending on the catalytic system, an activation of either the CÀC multiple bond or the NÀH bond takes place; the former activation occurs in the case of (4), and the latter type takes place in the cases of (1)-(3). Concerning the latter type, the NÀH bond is converted into either metal-imide intermediates (for example, RN = Ti) or metal-amide intermediates (for example, R 2 N À Ln). Two other important aspects of hydroamination are a) the relative difficulty in achieving intermolecular hydroamination as compared to the intramolecular version and b) the relative ease in achieving the hydroamination of alkynes compared to that of alkenes. Concerning the hydroamination of allenes, [7] the intramolecular reaction is well-studied in comparison with the

Effects of Homogeneous Irradiation of Electron Beam with Low Potential on Microscopic Fracture Resistance of Borosilicate Glass Surface

“…3,[11][12][13] The specimen was homogeneously irradiated with an electron beam through a titanium window attached to a 240-mm-diameter vacuum chamber. A tungsten filament in a vacuum was used to generate the electron beam with an electrical potential of 170 kV and an irradiating current of 2.0 mA.…”

“…[11][12][13] Homogeneous irradiation of electron beam with low potential (HIEBL) generates dangling bonds, 14,15) as well as annihilates the crack, resulting in the strengthening. 3,[11][12][13] The high stress resistance to propagate cracks and to nucleate crack origins macroscopically dominates the high fracture resistance. However, influence of HIEBL on the fracture resistance has not been reported.…”

Fluorocarbon compatibilized gold-silica nanocomposites for recyclable regioselective hydroamination of alkynes in a fluorous biphasic system

“…Late transition metals (Ir, Pd, Au, Rh) are highly attractive and desirable for asymmetric hyroaminations due to higher functional group tolerance for both inert-and intramolecular variants, lowest air and moisture sensitivity and provide higher enantioselectivities [19]. However, to date there are only a few reports of gold-catalyzed enantioselective hydroamination reactions, for instance the catalysts reported were dinuclear gold(I)-phosphine complexes with biaryl-based backbone [20].…”

Effects of Electron Beam Irradiation on Impact Value of Borosilicate Glass

“…12,13) Homogeneous EB-irradiation with lowvoltage generates dangling bonds 12,13) and then eliminates the crack, resulting in strengthening. 12,13) In addition, our research unit recently starts to report that the high stress resistance to crack origin nucleation as well as to crack propagation dominates the high fracture resistance of borosilicate glass. 14) However, the influence of EB-irradiation on the Charpy impact value (a uc ), one of indicator of practical fracture resistance, has not been reported for borosilicate glass.…”