An enantioselective Rh -catalyzed conjugate addition reaction of α-substituted β-nitroacrylates with various arylboronic acids by using chiral Rh 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 β -amino acid, (R)-2-(aminomethyl)-2-phenylpropanoic acid, and to the β -lactam, (R)-3-methyl-3-phenylazetidin-2-one. In addition, a tripeptide, which comprised l-phenylalanine, l-alanine, and β -amino acid 7, was also synthesized.

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.

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.E nantioenriched β-amino sulfone derivatives are versatile synthons in synthetic chemistry 1,2 and display a wide range of biological activities as compounds of medicinal importance. 3 For example, the oral drug apremilast (Otezla) (Figure 1), which is an inhibitor of phosphodiesterase 4

An enantioselective addition of arylboronic acids and a-ketoesters promoted by a Rhodium(I)chiral diene catalyst is reported. The transformation proceeds regioselectively in the presence of as low as 0.5 mol% of the catalyst generated in situ from a Rhodium(I) salt and diene L1, which is a bicyclo[2.2.1] ligand scaffold bearing 2,5 dinaphthyl substituents, to afford tertiary chiral a-hydroxy esters with high stereoselectivities (90-99% ee's) and in 50-> 99% yields. The method provides an expeditious and enantioselective synthesis of (S)-flutriafol.

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 β-amino acids. The applicability of this transformation is demonstrated by converting 3aa into the β-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.