The First In(OTf)3-Catalyzed Conversion of Kinetically Formed Homoallylic Alcohols into the Thermodynamically Preferred Regioisomers: Application to the Synthesis of 22α-Sterols
摘要:
A retro-ene reaction that generates the parent aldehyde and a sigmatropic rearrangement are involved in the In(OTf)3 -catalyzed conversion of homoallylic alcohols 1 into the thermodynamically favored regioisomers 2. This method can be used for the stereocontrolled synthesis of linear homoallylic 22α-sterols from their readily accessible branched 22β isomers.
Cooperative Titanocene and Phosphine Catalysis: Accelerated C–X Activation for the Generation of Reactive Organometallics
作者:Lauren M. Fleury、Andrew D. Kosal、James T. Masters、Brandon L. Ashfeld
DOI:10.1021/jo301726v
日期:2013.1.18
transmetalation approach toward the generation of Grignard and organozinc reagents mediated by a titanocene catalyst. This method enables the metalation of functionalized substrates without loss of functional group compatibility. Allyl zinc reagents and allyl, vinyl, and alkyl Grignard reagents were generated in situ and used in the addition to carbonyl substrates to provide the corresponding carbinols in yields
Allylic tin(IV)-tin(II) chloride-acetonitrile as a novel system for allylation of carbonyls or imines
作者:Makoto Yasuda、Yoshihiro Sugawa、Akihiro Yamamoto、Ikuya Shibata、Akio Baba
DOI:10.1016/0040-4039(96)01285-3
日期:1996.8
Effective allylation of aldehydes, ketones and imines was accomplished by allylic tributyltins 1 in the presence of SnCl2 in an acetonitrile solution. In this reaction system. Sn(IV)Sn(II) transmetallation must play a key role, generating the allylictin(II) reagents as a novel reacting species. Acetonitrile effectively promoted the transmetallation to give anti-adducts in the reaction with cinnamyltin
A Novel Synthesis of (
<i>E</i>
)‐2‐Alkenylborane from Chiral Borane and Diazoalkene: Asymmetric Alkenylboration of Aldehydes
作者:Gyungah Pak、Jimin Kim
DOI:10.1002/bkcs.11909
日期:2019.12
Asymmetric alkenylboration of aldehydes.
醛的不对称烯基硼化。
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.
Development of a Highly α-Regioselective Metal-Mediated Allylation Reaction in Aqueous Media: New Mechanistic Proposal for the Origin of α-Homoallylic Alcohols
This paper described a general method to obtain α-adduct homoallylic alcohols using indium, zinc, and tin in water. A new mechanism was proposed to account for the formation of these synthetically difficult-to-obtain molecules. Generally, this method can be performed with a wide range of aldehydes and allylic halides with just 6 equiv of water added, giving the α-adduct in high selectivities. To account