2565-39-1Relevant articles and documents
Atroposelective Synthesis of Axially Chiral N-Arylpyrroles by Chiral-at-Rhodium Catalysis
Chen, Shuming,Han, Feng,Houk, K. N.,Ivlev, Sergei,Meggers, Eric,Xie, Xiulan,Ye, Chen-Xi
supporting information, p. 13552 - 13556 (2020/06/05)
A transformation of fluxional into configurationally stable axially chiral N-arylpyrroles was achieved with a highly atroposelective electrophilic aromatic substitution catalyzed by a chiral-at-metal rhodium Lewis acid. Specifically, N-arylpyrroles were alkylated with N-acryloyl-1H-pyrazole electrophiles in up to 93 percent yield and with up to >99.5 percent ee, and follow-up conversions reveal the synthetic utility of this new method. DFT calculations elucidate the origins of the observed excellent atroposelectivity.
Three-step synthetic pathway to fused bicyclic hydantoins involving a selenocyclization step
?mit, Biljana M.,Pavlovi?, Radoslav Z.
, p. 1101 - 1108 (2015/01/30)
Sequential 5-alkenyl hydantoin and pyrrolidine ring-forming reactions have been applied in the synthesis of conformationally constrained fused bicyclic scaffold. They are assembled by a three-step reaction sequence from two variable building blocks (readily available β-ketoesters and alkenyl halides) by combining a Bucherer-Bergs reaction with a final selenium-promoted intramolecular cyclization as a key step. The chemoselectivity of this bicyclic hydantoin formation is strongly influenced by experimental factors such as the solvent and the use of additives. The reaction is regiospecific giving only five-membered fused bicyclic hydantoins in good to excellent yields stemming from the nucleophilic attack of the nitrogen atom to a cyclic seleniranium ion intermediate during the cyclization step. A separable diastereomeric mixture is obtained; the products with bridgehead substituents and phenylseleno groups in cis relationships were formed predominantly. The reaction tolerates a variety of substitution at the double bond, furthermore, the presence of substituents at C(5) and N(3) position opens up the capability of generating a broad structural diversity.
Cp*Ru(PN) complex-catalyzed isomerization of allylic alcohols and its application to the asymmetric synthesis of muscone
Ito, Masato,Kitahara, Sachiko,Ikariya, Takao
, p. 6172 - 6173 (2007/10/03)
Highly efficient isomerization of allylic alcohols into saturated carbonyls is accomplished using the catalyst system of Cp*RuCl[Ph2P(CH2)2NH2-κ2-P,N]-KOt-Bu (Cp* = η5-C5(CH3)5) under mild conditions. Mechanistic consideration based on isotope-labeling experiments indicated the present reaction is applicable to the asymmetric isomerization of racemic sec-allylic alcohols with a prochiral olefin via dynamic kinetic resolution. A concise asymmetric synthesis of muscone has been achieved, where the asymmetric isomerization using an optically active ligand is a key reaction. Copyright
