Catalytic TMSCl promoted powerful aldol addition and Claisen condensation mediated by TiCl4/Bu3N agent: comparison and evaluation with the Mukaiyama aldol addition
catalyst (0.05 equiv) signifiantly promoted the TiCl4/Bu3N-mediated direct cross aldol additions of sterically crowded ketones and α-hetero substituted ketones, and also the direct Claisencondensation between methyl esters.
MSCl催化剂(0.05当量)显着促进了空间拥挤的酮和α-杂取代的酮的TiCl 4 / Bu 3 N介导的直接交叉羟醛加成,以及甲酯之间的直接Claisen缩合。
Preparation of Enolates from<i>α</i>-Haloketones with<i>n</i>-BuLi, PhMgBr, or Et<sub>2</sub>Zn<i>via</i>Halogen-Metal Exchange Reaction
作者:Yoshitaka Aoki、Koichiro Oshima、Kiitiro Utimoto
DOI:10.1246/cl.1995.463
日期:1995.6
Metal-halogen exchange of α-iodoketones was performed upon treatment with n-BuLi, PhMgBr, Et2Zn or Me3Al in ether at 0 °C to give the corresponding metal enolates which reacted with aldehydes to provide the aldol type products in good yields.
2-iodo-1-(4-methoxyphenyl)propan-1-one, 2-iodopentan-3-one, 2-iodo-2-methyl-1-phenylpropan-1-one, 3,4-dihydro-2-iodo-1(2H)-naphthalenone, 2-iodo-1-phenylethan-1-one and 1-iodo-4-phenylbutan-2-one with 9-borabicyclo[3.3.1]nonane (9-BBN). Aldols were produced in good yields with good to high diastereoselectivities by subsequent reaction of boron enolates thus formed with various aldehydes. Several boron enolates derived