Cu(I)- or Ag(I)-Catalyzed Regio- and Stereocontrolled trans-Hydrofluorination of Ynamides

Abstract

With Et3N·3HF as the fluorinating reagent, a copper(I)- or silver(I)-catalyzed β/α-site-regiocontrolled trans-hydrofluorination of alkynamides has been achieved, affording the corresponding fluoro enamides in moderate to nearly quantitative yields with high regio- and stereoselectivity, respectively. The reaction proceeds under mild reaction conditions and exhibits good functional group tolerance. Further, the deuterium-labeling experiment confirmed the existence of the alkenylcopper intermediate.

A HF Loaded Lewis‐Acidic Aluminium Chlorofluoride for Hydrofluorination Reactions

“…At 0 °C, more than 70 % yield of the corresponding Markownikow alkyl fluorides as products were obtained. Recently, many research groups focus on gold‐based catalysts in combination with HF‐sources to develop hydrofluorination processes of alkynes . Indeed, the groups of Nolan, Toste, Miller, and Sadighi, used Et 3 HF⋅3 HF together with various catalysts and succeeded in the formation of monofluorinated alkenes .…”

Revealing the Intrinsic Nanohardness of Lath Martensite in Low Carbon Steel

“…The best fitting gives the values of f for the large and small martensite blocks as 1.2 and 1.05, respectively. A higher value of f represents a lower GND density within the plastic zone [8] so that the large martensite block has a lower nanohardness than the small martensite block. The small martensite block where the indent locates has densely distributed lath boundaries and is almost free of carbides (Figure 4(b)).…”

“…[4,6] The mechanical property of martensite block has been studied using the nanoindentation technique. [7][8][9][10][11][12] The intrinsic nanohardness of martensite block, which excludes the boundary effects, is mainly determined by dislocation strengthening, solid solution strengthening (including the interstitial C atoms), and precipitation strengthening. Such intrinsic nanohardness can be revealed by nanoindentation tests on the individual martensite blocks.…”

“…[4,5] The high-angle boundary can stop the transmission of dislocation and confine the indentation plastic zone, thus contributing to the nanohardness of martensite block, if the nanoindentation tests are close to the highangle boundaries. [8,13] Therefore, avoiding the contribution of the high-angle boundary in order to obtain the intrinsic nanohardness of the martensite block is required. This can be realized through the postanalysis on the indentation impressions using scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) combined with the detailed analysis on the indentation load displacement (P-h) curve.…”

Stereodivergent Alkyne Hydrofluorination Using a Simple Practical Reagent

“…A more direct method to access vinyl fluorides is the hydrofluorination of alkynes, substrates that are easily accessed from a variety of commercially available starting materials. Several strategies for the hydrofluorination of alkynes have been developed in recent years [20][21][22][23][24][25][26][27][28] . These include the coinage metal-catalyzed hydrofluorination of alkynes using various Lewis base adducts of hydrogen fluoride (Fig.…”