Nickel-catalyzed enantioselective hydrovinylation of silyl-protected allylic alcohols: An efficient access to homoallylic alcohols with a chiral quaternary center
Asymmetric hydrovinylation of silyl-protected allylicalcoholscatalyzed by nickel complexes of chiral spiro phosphoramidite ligands was developed. A series of homoallylicalcohols with a chiral quaternary center were produced in high yields (up to 97%) and high enantioselectivities (up to 95% ee). The reaction provides an efficient method for preparing bifunctional compounds with a chiral quaternary
Construction of a quaternary carbon center via cyclic sulfite
作者:Nanae Nishimura、Oyo Mitsunobu
DOI:10.1016/s0040-4039(00)00315-4
日期:2000.4
Reaction of (S)-2-oxo-4-methyl-4-phenyl-1,3,2-dioxathiolane with triethylaluminum selectively took place at the tertiarycarbinol center to give (R)-2-methyl-2-phenyl-1-butanol. Enhanced stereoselectivity was obtained in a nonpolar solvent. Similarly, a series of (S)-4,4-disubstituted-1,3,2-dioxathiolanes reacted with trimethylaluminum to afford the corresponding (R)-2-alkyl-2-phenyl-1-propanols in
Phosphonate-Directed Catalytic Asymmetric Hydroboration: Delivery of Boron to the More Substituted Carbon, Leading to Chiral Tertiary Benzylic Boronic Esters
作者:Suman Chakrabarty、James M. Takacs
DOI:10.1021/acscatal.8b03591
日期:2018.11.2
boronic esters. Hydroboration is catalyzed by a chiral rhodium catalyst prepared in situ from a Rh(I) precursor in combination with a simple TADDOL-derived chiral cyclic monophosphite in a 1:1 ratio. The regio- and stereochemistry arise from the combined effects of the relative disposition of the directing group to the alkene, the alkene substitution pattern, and the necessity of an arylsubstituent attached
Studies in Stereochemistry. XXIII. The Preparation and Complete Resolution of the 1,2-Diphenyl-2-methyl-1-butanol System<sup>1</sup>
作者:Donald J. Cram、Janet Allinger
DOI:10.1021/ja01647a003
日期:1954.9
Modular, Catalytic Enantioselective Construction of Quaternary Carbon Stereocenters by Sequential Cross-Coupling Reactions
作者:Bowman Potter、Emma K. Edelstein、James P. Morken
DOI:10.1021/acs.orglett.6b01580
日期:2016.7.1
chiral γ,γ-disubstituted allylboronates in the presence of RuPhos ligand occurs with high regioselectivity and enantiospecificity, furnishing nonracemic compounds with quaternary centers. Mechanistic experiments suggest that the reaction occurs by transmetalation with allyl migration, followed by rapid reductive elimination.