Catalytic Asymmetric Allylation of Ketones and a Tandem Asymmetric Allylation/Diastereoselective Epoxidation of Cyclic Enones
作者:Jeung Gon Kim、Karen M. Waltz、Iliana F. Garcia、David Kwiatkowski、Patrick J. Walsh
DOI:10.1021/ja047758t
日期:2004.10.1
titanium tetraisopropoxide, BINOL, 2-propanol additive, and tetraallylstannane as allylating agent. A variety of ketone substrates, including acetophenone derivatives and alpha,beta-unsaturated cyclic enones, reacted to form tertiary homoallylic alcohols in good yields (67-99%) and with high levels of enantioselectivity (generally >80%). A novel one-pot enantioselective allylation/diastereoselective
Rhodium-Catalyzed Kinetic Resolution of Tertiary Homoallyl Alcohols via Stereoselective Carbon−Carbon Bond Cleavage
作者:Ryo Shintani、Keishi Takatsu、Tamio Hayashi
DOI:10.1021/ol800120p
日期:2008.3.1
A nonenzymatic kinetic resolution of tertiary homoallyl alcohols has been developed through a rhodium-catalyzed retro-allylation reaction under simple conditions. Selectivity factors of up to 12 have been achieved by employing (R)-H8-binap as the ligand, and the reaction can be conducted on a preparative scale.
The first example of catalyticenantioselective allylboration and crotylboration of simple ketones is described. High enantioselectivity (up to 93% ee) was obtained using 3 mol % CuF-iPr-DuPHOS as a chiral catalyst and 4.5 mol % La(OiPr)3 as a cocatalyst. Mechanistic studies strongly suggested that the active nucleophile of the present reaction is an allylcopper, and that La(OiPr)3 facilitates the
Silver-Catalyzed Asymmetric Sakurai−Hosomi Allylation of Ketones
作者:Manabu Wadamoto、Hisashi Yamamoto
DOI:10.1021/ja0553351
日期:2005.10.1
allylation of simple ketones. A significaant improvement of the reactivity was observed by using THF as the solvent. The catalyst turnover was increased by addition of 1 equiv of MeOH. AgF and (R)-DIFLUORPHOS predominantly formed a 1:1 complex that provided high enantioselectivity. This catalyst system can be applied to various simple ketones, and corresponding tertiaryhomoallylicalcohols were obtained
Complexes of (S)-pipecolic acid-, l-proline-, and other amino acid-derived N,N‘-dioxides coordinated with different metal ions have been investigated in the enantioselective allylation of ketones. A variety of aromatic ketones were found to be suitable substrates in the presence of the L1-In(III) complex, and afforded the corresponding homoallylic alcohols with good enantioselectivites (up to 83% ee)