18700-70-4Relevant academic research and scientific papers
Chiral phosphoramide-catalyzed enantioselective addition of allylic trichlorosilanes to aldehydes. Preparative studies with bidentate phosphorus-based amides
Denmark, Scott E.,Fu, Jiping,Lawler, Michael J.
, p. 1523 - 1536 (2006)
On the basis of the mechanistic insight that more than one Lewis basic moiety (phosphoramide) is involved in the rate- and stereochemistry-determining step of enantioselective allylation, bidentate chiral phosphoramides were developed. Different chiral phosphoramide moieties were connected by tethers of methylene chains of varying length. The rate and enantioselectivity of allylation with allyltrichlorosilane promoted by the bidentate phosphoramides was found to be highly dependent on the tether length. A new phosphoramide based on a 2,2′-bispyrrolidine skeleton has been designed and afforded good yield, efficient turnover, and high enantioselectivity in allylation reactions. The synthesis of enantiopure 2,2′-bispyrrolidine was easily accomplished on large scale by photodimerization of pyrrolidine followed by resolution with L(or D)-tartaric acid. The scope of the allylation reaction was examined with variously substituted allylic trichlorosilanes and unsaturated aldehydes. This method has been applied to the construction of stereogenic, quaternary centers by the addition of unsymmetrically γ-disubstituted allylic trichlorosilanes.
Compounds with Bridgehead Nitrogen Part 64 - Conformational Equilibria in the 6-p-Nitrophenylperhydrodipyridoimidazoles
Banting, Lee,Crabb, Trevor A.
, p. 1035 - 1039 (2007/10/02)
The effect of 6-substitution on the conformational equilibria of the perhydrodipyridoimidazoles has been investigated. r-6H,t-11a,t-11b-6-p-Nitrophenylperhydrodipyridoimidazole was found to exist as a pair of enantiomeric non-interconverting N-outside-cis-syn-trans-conformers, whereas the r-6H,c-11a,c-11b and r-6H,c-11a,t-11b isomers adopted the trans-syn-trans conformations.Both syn isomers exhibit restricted rotation of the 6-p-nitrophenyl substituent at room temperature and below.
