trans-1-Sulfonylamino-2-isoborneolsulfonylaminocyclohexane Derivatives: Excellent Chiral Ligands for the Catalytic Enantioselective Addition of Organozinc Reagents to Ketones
作者:Vicente J. Forrat、Oscar Prieto、Diego J. Ramón、Miguel Yus
DOI:10.1002/chem.200501397
日期:2006.5.24
The catalytic enantioselectiveaddition of different organozinc reagents (such as alkyl and aryl derivatives or in situ generated aryl, allyl alkenyl, and alkynyl derivatives obtained through different transmetallation processes) to simple ketones has been accomplished by using titanium tetraisopropoxide and chiral ligands derived from substituted trans-1-sulfonylamino-2-isoborneolsulfonylaminocyclohexane
Harnessing the Power of the Asymmetric Grignard Synthesis of Tertiary Alcohols: Ligand Development and Improved Scope Exemplified by One-Step Gossonorol Synthesis
作者:Saranna E. Kavanagh、Declan G. Gilheany
DOI:10.1021/acs.orglett.0c02629
日期:2020.11.6
A series of N-substituted cyclohexyldiaminophenolic ligands for the asymmetric Grignard synthesis of tertiary alcohols is reported. The 2,5-dimethylpyrrole-decorated ligand led to improved enantioselectivities and broadened the scope of the methodology. As an exemplar, we report an unprecedented highly selective one-step synthesis of gossonorol in 93% ee, also constituting the shortest formal syntheses
Chiral diamine compounds for the preparation of chiral alcohols and chiral amines
申请人:University College Dublin
公开号:US10196338B2
公开(公告)日:2019-02-05
Processes for stereoselective preparation of a chiral alcohol or a chiral amine are described. The processes include reacting a first prochiral reactant selected from the group consisting of a ketone, an aldehyde, and an imine, with a second reactant that includes a Grignard reagent, in the presence of a chiral trans-diamine of formula (1) as defined herein:
Reactions of Et<sub>3</sub>ZnLi with Ketones: Electronic and Steric Effects<sup>1</sup>
作者:Curtis A. Musser、Herman G. Richey
DOI:10.1021/jo000630j
日期:2000.11.1
Toluene solutions of composition Et3ZnLi react rapidly with aldehydes and ketones to form addition products. Et3ZnNa and Et3ZnK solutions react readily with the same substrates although metalation, as well as addition, is significant with substrates having alpha -hydrogens. The Et3ZnM solutions react with 2-cyclohexenone to give mainly the 1,4-addition product. Relative rates of addition of Et3ZnLi to substituted acetophenones give a Hammett rho of 2.78. Addition of Et3ZnLi to acetophenone is sf owed significantly by alpha and ortho methyl substituents; relative rates of addition to acetophenone, o-methylacetophenone, and tert-butyl phenyl ketone are 1.00, 0.012, and 0.003.
ADLINGTON M. G.; ORFANOPOULOS M.; FRY J. L, TETRAHEDRON LETT. <TELE-AY>, 1976, NO 34, 2955-2958