757195-52-1Relevant academic research and scientific papers
Phosphonate analogs of N-benzoyl-and N-Boc-3-phenylisoserine, the taxol C-13 side chain
Wroblewski, Andrzej E.,Piotrowska, Dorota G.
, p. 8123 - 8132 (1998)
Diastereoselectivity of the addition of diethyl phosphite to N-Boc-phenylglycinal reached 50% when NEt3 or KF were used as catalysts but employing lithium diethyl phosphonate lower d.e. was obtained. Separation of the required syn diethyl 2-[(tert- butoxycarbonyl)amino]-1-hydroxy-2-phenylethylphosphonate (8a) from the antiisomer 8b was best achieved as O-benzoate 10a or O- trimethylsilyl 9a derivatives. Diethyl 2-(benzoylamino)-1-hydroxy- 2-phenylethylphosphonate (12a) was efficiently prepared (HCl- AcOEt) from 10a in a one-step procedure. The absolute configuration at C-1 in 8a and 8b was established from 1H and 13C NMR spectral data of their N,O-isopropylidene derivatives. Acyclic phosphonates from the a series (8, 10, 12) adopt antiperiplanar conformations.
Enantioselective synthesis of primary 1-(aryl)alkylamines by nucleophilic 1,2-addition of organolithium reagents to hydroxyoxime ethers and application to asymmetric synthesis of G-protein-coupled receptor ligands
Atobe, Masakazu,Yamazaki, Naoki,Kibayashi, Chihiro
, p. 5595 - 5607 (2007/10/03)
(E)-Arylaldehyde oxime ethers bearing a (1S)-2-hydroxy-1-phenylethyl or (2R)-1-hydroxy-2-phenylethyl group as a chiral auxiliary, both derived from a single precursor, methyl (R)-mandelate, underwent nucleophilic addition with organolithium reagents via six-membered chelates to give the diastereomerically enriched (R)- and (S)-adducts, respectively, which, after chiral auxiliary removal by reductive N-O bond cleavage, led to the corresponding (R)- and (S)-1-(aryl)ethylamines. This organolithium addition protocol using methyllithium was applied in an enantiodivergent fashion to the preparation of both enantiomers of 1-(2-hydroxyphenyl)ethylamine, which has been previously used as an efficient chiral auxiliary for the synthesis of natural products in this laboratory. The synthetic utility of this methodology involving diastereoselective methyl addition was demonstrated by further application to the asymmetric synthesis of a new type of calcium receptor agonist (calcimimetics), (R)-(+)-NPS R-568 and its thio analogue. Furthermore, diastereoselective vinylation was accomplished by application of the hydroxy oxime ether-based protocol using vinyllithium, which allowed the development of the enantioselective synthesis of the NK-1 receptor antagonists, (+)-CP-99,994 and (+)-CP-122,721.
Enantioselective synthesis of NK-1 receptor antagonists (+)-CP-99,994 and (+)-CP-122,721
Yamazaki, Naoki,Atobe, Masakazu,Kibayashi, Chihiro
, p. 7979 - 7982 (2007/10/03)
An enantioselective total synthesis of NK-1 receptor antagonists, (+)-CP-99,994 and (+)-CP-122,721, is described. The key steps are diastereoselective addition of vinyllithium to a chiral benzaldehyde oxime ether and diastereoselective borane reduction of
