Hydrogen-Bond-Activated Palladium-Catalyzed Allylic Alkylation via Allylic Alkyl Ethers: Challenging Leaving Groups
摘要:
C-O bond cleavage of allylic alkyl ether was realized in a Pd-catalyzed hydrogen-bond-activated allylic alkylation using only alcohol solvents. This procedure does not require any additives and proceeds with high regioselectivity. The applicability of this transformation to a variety of functionalized allylic ether substrates was also investigated. Furthermore, this methodology can be easily extended to the asymmetric synthesis of enantiopure products (99% ee).
STEREOSELECTIVE FORMATION OF (E)-1-ALKENYL ETHERS. THE COUPLING REACTION OF 1,3- OR 3,3-DIETHOXY-1-PROPENE WITH GRIGNARD REAGENTS CATALYZED BY NICKEL–PKOSPHINE COMPLEX
作者:Hideyuki Sugimura、Hisashi Takei
DOI:10.1246/cl.1985.351
日期:1985.3.5
1,3- or 3,3-Diethoxy-1-propene reacted with Grignard reagents in the presence of nickel-phosphine complex to give (E)-1-alkenyl ethers stereoselectively.
Acid-catalyzed organic reactions, such as etherification, esterification, acetal synthesis, cleavage, and interconversion, and pinacol rearrangement were carried out in the presence of catalytic amounts of o-benzenedisulfonimide as Bronsted acidcatalyst; the conditions were mild and selective. The catalyst was easily recovered and purified, ready to be used in further reactions, with economic and ecological
Regioselective and Enantioselective Iridium-Catalyzed Allylation of Enamines
作者:Daniel J. Weix、John F. Hartwig
DOI:10.1021/ja071455s
日期:2007.6.1
hours at room temperature and encompass the reactions of aromatic and aliphatic methyl ketone derivatives. The enamines of methyl alkyl ketones, which exist as a mixture of two regioisomers, reacted selectively (≥99:1) at the less hindered position. The use of a preformed cyclometalatediridiumcatalyst, isopropyl carbonates, toluene solvent, and ZnCl2 as an alcohol adsorbent was important for the development
The synthesis and reactivity of propargylic and allylic trifluoromethanesulfinates under various conditions has been investigated. Propargylic esters readily undergo (2,3)-sigmatropic rearrangement to the corresponding allenyl trifluoromethyl sulfones, even under solvolytic conditions. An unusually facilenucleophilic addition of the solvent to the allenyl sulfone under the latter conditions has also
Enantioselective and Diastereodivergent Allylation of Propargylic C–H Bonds
作者:Jin Zhu、Yidong Wang、Aaron D. Charlack、Yi-Ming Wang
DOI:10.1021/jacs.2c07297
日期:2022.8.31
An iridium-catalyzed stereoselective coupling of allylicethers and alkynes to generate 3,4-substituted 1,5-enynes is reported. Under optimized conditions, the coupling products are formed with excellent regio-, diastereo-, and enantioselectivities, and the protocol is functional group tolerant. Moreover, we report conditions that allow the reaction to proceed with complete reversal of diastereoselectivity