Nickel-Catalyzed Asymmetric Hydrogenation of Cyclic Sulfamidate Imines: Efficient Synthesis of Chiral Cyclic Sulfamidates

Abstract

Summary Chiral cyclic sulfamidates are useful building blocks to construct compounds, such as chiral amines, with important applications. Often these compounds can only be generated through expensive precious metal catalysts. Here, Ni(OAc) 2 /( S , S )-Ph-BPE-catalyzed highly efficient asymmetric hydrogenation of cyclic sulfamidate imines was successfully developed, affording various chiral cyclic sulfamidates with high yields and excellent enantioselectivities (up to 99% yield, >99% enantiomeric excess [ee]). This Ni-catalyzed asymmetric hydrogenation on a gram scale has been achieved with only 0.1 mol% catalyst loading in 99% yield with 93% ee. Other types of N -sulfonyl ketimines were also hydrogenated well to obtain the corresponding products with >99% conversion, 96%–97% yields, and 97%–>99% ee. In addition, this asymmetric methodology could produce other enantioenriched organic molecules, such as chiral β-fluoroamine, amino ether, and phenylglycinol. Moreover, a reasonable catalytic cycle was provided according to the deuterium-labeling studies, which could reveal a possible mechanism for this Ni-catalyzed asymmetric hydrogenation.

Recyclable cooperative catalyst for accelerated hydroaminomethylation of hindered amines in a continuous segmented flow reactor

“…The heterolytic cleavage of the H-H bond is believed to be more facile than the homolytic oxidative addition that results in Rh dihydride. Similar effect has been proposed for Co 23 , Ni 34 , and Ru 35 catalysts. Ligand exchange between 2F and the enamine results in the formation of the Rh hydride amine complex iii that can undergo hydride transfer to the unsaturated C=C bond.…”

Ni-catalyzed asymmetric hydrogenation of N-aryl imino esters for the efficient synthesis of chiral α-aryl glycines

“…In view of current interest in the development of earthabundant metal catalysts in asymmetric hydrogenation [31][32][33][34][35][36][37][38][39][40][41] , which are inexpensive and environmentally friendly, the use of nickel has drawn increasing attention 24,[31][32][33][34][35][36][37][38][39][40][41] . Although Nicatalyzed asymmetric reduction has seen rapid development, the asymmetric hydrogenation of imines is still in its infancy 24,[42][43][44] . To date, only a few Ni-catalyzed asymmetric hydrogenations of imines have been reported by Zhang 24,43,44 and our group 42 , and the imines substrates are all activated by N-sulfonyl groups (Fig.…”

“…Although Nicatalyzed asymmetric reduction has seen rapid development, the asymmetric hydrogenation of imines is still in its infancy 24,[42][43][44] . To date, only a few Ni-catalyzed asymmetric hydrogenations of imines have been reported by Zhang 24,43,44 and our group 42 , and the imines substrates are all activated by N-sulfonyl groups (Fig. 1c).…”

A diversity of recently reported methodology for asymmetric imine reduction

“…Focusing on the substrate scope it was found that substituted phenyl groups affords improved results in some cases and enantioselectivities of 83-99%. 44 Diphosphine ligand 2 was also found to be effective in the Pd-catalysed AH of sulfonyl imines. The system proved effective under a low hydrogen pressure and in the presence of Lewis acids.…”