119839-47-3Relevant academic research and scientific papers
A New Ligand Design Based on London Dispersion Empowers Chiral Bismuth-Rhodium Paddlewheel Catalysts
Singha, Santanu,Buchsteiner, Michael,Bistoni, Giovanni,Goddard, Richard,Fürstner, Alois
supporting information, p. 5666 - 5673 (2021/05/05)
Heterobimetallic bismuth-rhodium paddlewheel complexes with phenylglycine ligands carrying TIPS-groups at the meta-positions of the aromatic ring exhibit outstanding levels of selectivity in reactions of donor/acceptor and donor/donor carbenes; at the same time, the reaction rates are much faster and the substrate scope is considerably wider than those of previous generations of chiral [BiRh] catalysts. As shown by a combined experimental, crystallographic, and computational study, the new catalysts draw their excellent application profile largely from the stabilization of the chiral ligand sphere by London dispersion (LD) interactions of the peripheral silyl substituents.
SYNTHESIS OF α-AMINO ACIDS WITH β,γ-UNSATURATED SIDE CHAINS
Castelhano, Arlindo L.,Horne, Stephen,Taylor, Gregg J.,Billedeau, Roland,Krantz, Allen
, p. 5451 - 5466 (2007/10/02)
α-Amino acids with allenyl, vinyl and acetylenic side chains can be synthesized using non-enolate based strategies.The ester enolate-Claisen rearrangement applied to propargylic esters of N-protected α-amino acids is of limited utility since only poor yields of allenic product are obtained with the N-Boc glycine esters, the system which give the most reproducible results.However, α-allenyl-α-amino acids that are fully functionalized on the α-carbon are available through the agency of 4-allenyl-2-phenyloxazolones 4 ( obtained from propargyl esters of N-benzoyl protected amino acids via cyclization and Claisen rearrangement ) provided that Meerwein's reagent is used to facilitate hydrolysis of the benzamide function in 5.A variety of α-substituted glycinates, including those with α-vinyl and α-acetylenic functions, can be prepared using a two step sequence involving condensation of the cationic glycine synthon 22 with various organomagnesium reagents, followed by hydrolysis.
