10.1002/anie.201900442
The study presents an enantioselective rhodium-catalyzed allylic alkylation of β,γ-unsaturated α-amino nitriles, offering a novel approach to construct β-stereogenic carbonyl derivatives. This method leverages the catalytic asymmetric alkylation of a homoenolate equivalent, addressing the challenge of manipulating three modes of selectivity: regio- and enantioselectivity, as well as geometrical control. The g-stereogenic cyanoenamine products, resulting from the reaction, can be readily hydrolyzed to yield β-substituted carboxylic acids, providing a convenient pathway to various related carbonyl derivatives. The study underscores the critical role of the E-cyanoenamine products' selective formation, facilitated by the chiral rhodium-allyl intermediate, in achieving high enantiocontrol. The methodology not only provides a practical process but also highlights the utility of molecular dynamics simulation in guiding experimental research for the development of small-molecule inhibitors targeting toxic amyloidogenic protein oligomers.
10.1246/cl.1977.517
The study investigates the synthesis of 1,2-propanediol formates using carbon dioxide, hydrogen, and methyloxirane as direct starting materials, catalyzed by transition metal complexes such as tris(triphenylphosphine)chlororhodium. The researchers discovered a novel reaction where carbon dioxide was catalytically fixed with hydrogen and methyloxirane to form 1,2-propanediol formates (1a, 1b, and 2) as main products, along with by-products propylene carbonate (3) and 1,2-propanediol (4). The study highlights the significance of this reaction compared to previous ones, as it does not involve active-hydrogen compounds. Instead, an oxirane is used, which is expected to insert into the transition metal-formato bond to form an intermediate complex. The study also notes the formation of formic acid in the reaction products and suggests the possibility of another reaction path involving the direct reaction of formic acid with an oxirane.
Xi,
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