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The asymmetric conjugate addition of arylboronic acids to N-phthalimidodehydroalanine 1i catalyzed by Rh(I)/L1a enables the facile preparation of chiral functionalized phenylalanines. The reaction proceeds by a conjugate addition and enantioselective protonation cascade, affording a rhodium enolate that undergoes re-face protonation. The reaction tolerates various arylboronic acids and can be used in the gram-scale synthesis of (S)-phenylalanine hydrochloride, demonstrating the reaction scope and the synthetic feasibility of the process.

A chiral rhodium(I)-diene catalyst enabled the one-step synthesis of β-aryl β-imido sulfones under mild reaction conditions. By selection of the chiral diene ligand L1a or L2, each enantiomer of the chiral β-aryl β-imido sulfone target can be accessed with high stereoselectivity. Demonstration of the scope of the reaction, which includes the synthesis of an N-protected chiral β-amino β-phenyl sulfone, culminated with the efficient synthesis of the heteroatom-rich active pharmaceutical ingredient apremilast.

The highly enantioselective conjugate addition of a variety of arylboronic acids to β-nitroacrylates is reported to provide optically active α-aryl β-nitropropionates in up to 70% yields and >99.5% ee’s, which are useful building blocks for preparing chiral β2-amino acids. The applicability of this transformation is demonstrated by converting 3aa into the β2-amino acid 5 and transforming 3ap to β-amino ester 7 via reduction and reductive N-alkylation. The latter compound is a precursor for preparing ent-ipatasertib.

An enantioselective RhI-catalyzed conjugate addition reaction of α-substituted β-nitroacrylates with various arylboronic acids by using chiral RhI diene catalysts is described for the first time. The addition reaction proceeds under mild conditions in a range of common organic solvents and additives, and it affords the corresponding quaternary-carbon-containing α,α-disubstituted β-nitropropionate products in up to 63 % yield and 99 % ee. Reaction of either (E)- or (Z)-β-nitroacrylates provided the same enantiomer of the product, and a range of esters and aryl groups were tolerated. To demonstrate the utility of the method, ethyl (R)-1,1-methyl-1-phenyl-3-nitropropionate, prepared herein, was converted to the non-proteinogenic β2,2-amino acid, (R)-2-(aminomethyl)-2-phenylpropanoic acid, and to the β2,2-lactam, (R)-3-methyl-3-phenylazetidin-2-one. In addition, a tripeptide, which comprised l-phenylalanine, l-alanine, and β2,2-amino acid 7, was also synthesized.

Nanostructures of the collagen fibers play an important role in the corneal stroma. It influences the optical properties and transparency of the cornea. Several theoretical studies indicate that the cornea presents transparent because of the suitable diameter of collagen fibers, the arrangement between layers of the lamellar, and the refractive index of collagen fibers and fillers in the stroma [1]. The cornea is the transparent substance at the front of the eye. From the outside to the inside layers of the cornea are divided into epithelium, bowman’s layer, stroma, descemet’s membrane and endothelium. The thickness of the stroma is about 500 μm, which is about 90% of the total thickness of the cornea. It is made of 200 lamellar crystal layers which are stacked at an angle to each layers, and lamellar crystal consists type I and IV collagen fiber structure. In 1957, D. M. Mauurice proposed the theory of lattice arrangement in the fibrous structure of the corneal stroma layer [2].

The highly enantioselective conjugate addition of a variety of arylboronic acids to β-nitroacrylates is reported to provide optically active α-aryl β-nitropropionates in up to 70% yields and99.5% ee's, which are useful building blocks for preparing chiral β

The unprecedented development of asymmetric Rh-catalyzed 1,2-allylation of N-Ts- and N-Ns-aldimines is achieved. This protocol utilizes potassium allyltrifluoroborates and various aldimines to generate enantioenriched homoallylic amines in the presence of 3.0 mol % of Rh(I)/L1b catalyst with up to 90% yield, 98% ee (R = H), and 10:1 diastereoselectivity (R = Me or Ph), yielding the same major diastereomer when using potassium (E)- and (Z)-crotyltrifluoroborate. Its synthetic utility is also illustrated in the total synthesis of (−)-crispine A.

Clock gating is a useful technique to reduce power consumption of a synchronous sequential circuit. Conventionally, we use activity patterns, which are derived from a scheduled data flow graph and a module binding solution, to represent enable logics for clock gating. Based on activity patterns of modules, previous works utilize AND gates to construct activity-driven clock trees. In this paper, we demonstrate that, if we utilize OR gates at the bottom level, the power consumption at higher levels can be greatly reduced. From this observation, we propose a novel activity-driven clock tree design methodology, including a new tree structure and a corresponding design flow. Benchmark data show that our methodology can reduce 7.1% clock power consumption.

A series of 2-methyl-1,3-propenylene-bridged (η5-diarylphosphinocyclopentadienyl)(phosphine)manganese(I) dicarbonyl complexes 2 have been developed as a new class of phosphine-olefin ligands based on a planar-chiral transition-metal scaffold, which show the better robustness as well as the higher enantioselectivity over phosphine-olefin ligands 1 that are with a planar-chiral (η6-arene)chromium(0) framework. The practical enantiospecific and scalable synthesis of 2 has been established. Phosphine-olefin ligands 2 enable to construct the effective chiral environment around a transition-metal center upon coordination, and thus their rhodium(I) complexes exhibit excellent catalytic performances in the various asymmetric addition reactions of arylboron nucleophiles. Complex 2b, which is with bis(3,5-dimethylphenyl)phosphino group on the cyclopentadienyl ring, is found to be a superior chiral ligand in the rhodium-catalyzed asymmetric 1,4-addition reactions of arylboronic acids to various cyclic/acyclic enones giving the corresponding arylation products in over 99% ee. On the other hand, 2c and 2d, which are with bis[3,5-bis(trifluoromethyl)phenyl]phosphino and bis(3,5-di-tert-buthyl-4-methoxyphenyl)phosphino groups respectively, are highly efficient chiral ligands in the rhodium-catalyzed asymmetric 1,2-addition reactions of the arylboron nucleophiles to imines or aldehydes showing up to 99.9% ee. The X-ray crystallographic studies of (R)-2b and [RhCl((S*)-2b)]2 reveal the absolute configuration of 2b and its phosphine-olefin bidentate coordination to a rhodium(I) cation. Structural comparison with [RhCl((R*)-1b)]2 postulates the origins of the higher enantioselectivity of newly developed phosphine-olefin ligands 2.

An enantioselective Rh