C–O cleavage via InIII alkoxide intermediates: In situ 13C NMR analysis of the mechanism of an enantioselective in-mediated cyclopropanation reaction
作者:Jennifer L. Slaughter、Guy C. Lloyd-Jones
DOI:10.1016/j.tet.2020.131786
日期:2021.1
dibenzylideneacetone and benzylideneacetone by in situ generated allyl indium reagents in the presence of methyl mandelate as a chiral modifier has been studied by in situ 13C1H} NMR in conjunction with 13C/2H labelling and mass spectrometry. Two indium alkoxides were identified, the first arising from indium mediated allylation of the ketone, the second arising from reaction of an in situ liberated
通过原位13 C 1 H} NMR结合13 C / 2 H标记和质量研究了原位生成的烯丙基铟在手性改性剂存在下通过原位生成的烯丙基铟试剂对二苄叉基丙酮和苄叉基丙酮进行不对称环丙烷化的机理。光谱法。鉴定出两种铟醇盐,第一种是由铟介导的酮的烯丙基化产生的,第二种是由LiI介导的原位释放的均烯丙基与过量的烯丙基铟试剂的反应产生的。在酸化过程中,氧的质子化导致C–O而不是In–O裂解,并且初始的叔烯丙基阳离子被约90%的si立体选择性烯丙基化 通过假定为扁桃酸酯螯合的铟烯丙基试剂进行选择性。
Asymmetric Allylation of Ketones and Subsequent Tandem Reactions Catalyzed by a Novel Polymer-Supported Titanium-BINOLate Complex
作者:Jagjit Yadav、Gretchen R. Stanton、Xinyuan Fan、Jerome R. Robinson、Eric J. Schelter、Patrick J. Walsh、Miquel A. Pericas
DOI:10.1002/chem.201400204
日期:2014.6.2
asymmetric allylation of ketones. The catalyst showed good activity and excellent enantioselectivity, typically matching the results obtained in the corresponding homogeneous reaction. The allylation reaction mixture could be submitted to epoxidation by simple treatment with tert‐butyl hydroperoxide (TBHP), and the tandem asymmetricallylation epoxidation process led to a highly enantioenriched epoxy alcohol
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
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
Facial-Selective Allylation of Methyl Ketones for the Asymmetric Synthesis of Tertiary Homoallylic Ethers
作者:Lutz F. Tietze、Sören Hölsken、Jens Adrio、Tom Kinzel、Christoph Wegner
DOI:10.1055/s-2004-829153
日期:——
The stereoselective allylation of methyl ketones is described to give tertiary homoallylic ethers, which can easily be transformed into homoallylic alcohols by a Birch reduction. Reaction of methyl ketones 4 with allylsilane 5 in the presence of the chiral TMS ether 3a and a catalytic amount of trifluoromethanesulfonic acid led to homoallylic ethers 6 in high yield with a selectivity of 9:1 to >20:1