Mitsunobu approach to the synthesis of optically active α,α-disubstituted amino acids
Chiral tertiary α-hydroxy esters of known stereochemical configuration were transformed to α-azido esters by Mitsunobu reaction with HN3. Optimization of this reaction was shown to proceed at room temperature with high chemical yield using 1,1-(azodicarbonyl)dipiperidine (ADDP) and trimethylphosphine (PMe3). Complete inversion of configuration was observed at the α-carbon. Several α,α- disubstituted amino acids were synthesized in high overall chemical yield and optical purity.
Green, Jonathan E.,Bender, David M.,Jackson, Stona,O'donnell, Martin J.,Mccarthy, James R.
supporting information; experimental part
p. 807 - 810
(2009/08/08)
Stereospecific C-S bond formation from chiral tertiary alcohols by quinone-mediated oxidation-reduction condensation using alkyl diphenylphosphinites and its application to the synthesis of a chiral tertiary thiol
Oxidation-reduction condensation between 2-sulfanyl-1,3-benzothiazole (Btz-SH) and the alkyl diphenylphosphinites 1, prepared from tertiary alcohols, proceeded smoothly in the presence of 2,6-di-t-butyl-1,4-benzoquinone (DBBQ) and the corresponding S-alky