Rhodium-catalyzed carbonyl allylations by allylic alcohols with tin(II) chloride
作者:Yoshiro Masuyama、Yusuke Kaneko、Yasuhiko Kurusu
DOI:10.1016/j.tetlet.2004.10.051
日期:2004.11
Rhodium complexes such as [RhCl(cod)]2, [Rh(cod)2]BF4, and [Rh(cod)(CH3CN)2]BF4 function as catalysts for carbonylallylations by allylicalcohols with 1 equimolar amount of tin(II) chloride to each allylicalcohol and aldehyde in THF at 50 °C to produce the corresponding homoallylic alcohols.
Bi(cyclopentyl)diol-Derived Boronates in Highly Enantioselective Chiral Phosphoric Acid-Catalyzed Allylation, Propargylation, and Crotylation of Aldehydes
作者:Jinping Yuan、Pankaj Jain、Jon C. Antilla
DOI:10.1021/acs.joc.0c01646
日期:2020.10.16
catalytic addition of bi(cyclopentyl)diol-derived boronates to aldehydes promoted by chiralphosphoricacids, allowing for the formation of enantioenriched homoallylic, propargylic, and crotylic alcohols (up to >99% enantiomeric excess (ee), diastereomeric ratio (dr) >20:1). These boronate substrates provided superior enantioselectivities, allowing for the reactions to proceed with low catalyst loading
<i>anti</i>-Diastereo- and Enantioselective Carbonyl Crotylation from the Alcohol or Aldehyde Oxidation Level Employing a Cyclometallated Iridium Catalyst: α-Methyl Allyl Acetate as a Surrogate to Preformed Crotylmetal Reagents
作者:In Su Kim、Soo Bong Han、Michael J. Krische
DOI:10.1021/ja808857w
日期:2009.2.25
catalyst generated in situ from [Ir(cod)Cl](2), 4-cyano-3-nitrobenzoic acid and the chiral phosphine ligand (S)-SEGPHOS, alpha-methyl allyl acetate couples to alcohols 1a-1j with complete levels of branched regioselectivity to furnish products of carbonyl crotylation 3a-3j, which are formed with good levels of anti-diastereoselectivity and exceptional levels of enantioselectivity. An identical set of optically
在使用由[Ir(cod)Cl](2)、4-氰基-3-硝基苯甲酸和手性膦配体(S)-SEGPHOS原位生成的邻位环金属化铱催化剂进行转移氢化的条件下,α-甲基乙酸烯丙酯与具有完全支化区域选择性水平的醇1a-1j偶联,提供羰基巴豆酰化产物3a-3j,形成的产物具有良好水平的反非对映选择性和异常水平的对映选择性。在相同的条件下,但使用异丙醇作为末端还原剂,可以从相应的醛2a-2j得到一组相同的光学富集的羰基巴豆酰化产物3a-3j。旨在探索立体选择起源的实验建立了 (R)-乙酸酯和经 (S)-SEGPHOS 修饰的铱催化剂的匹配电离模式,以及烯丙基乙酸酯的可逆电离和快速 pi 面相互转化。在CC键形成之前产生吡啶基中间体。此外,还证明了在羰基加成之前的快速醇-醛氧化还原平衡。因此,在不存在任何化学计量金属试剂或化学计量金属副产物的情况下,实现了醇或醛氧化水平的反非对映选择性和对映选择性羰基巴豆酰化。
Rhodium-Catalyzed Allyl Transfer from Homoallyl Alcohols to Aldehydes via Retro-Allylation Followed by Isomerization into Ketones
Retro-allylation of homoallyl alcohol by rhodium catalysis occurs to generate allylrhodium species. This allylrhodium reacts with aldehydes to give the corresponding secondary alcohols in situ. Isomerization of these alcohols proceeds in the same pots to furnish the corresponding saturated ketones in good yields. [reaction: see text]
α-Regioselective carbonyl allylation by an allylic tin compound prepared from 1-bromobut-2-ene and tin(<scp>II</scp>) bromide at a nonpolar organic–aqueous interface
1-Bromobut-2-ene on a dichloromethane–water biphasic system at 25 °C causes α-regioselective addition to aldehydes with SnBr2 to produce 1-substituted pent-3-en-1-ols, and causes γ-regioselective addition to aldehydes with SnBr2–Bu4NBr to produce 1-substituted 2-methylbut-3-en-1-ols.