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).
Protecting group-free use of alcohols as carbon electrophiles in atom efficient aluminium triflate-catalysed dehydrative nucleophilic displacement reactions
作者:Adam Cullen、Alfred J. Muller、D. Bradley G. Williams
DOI:10.1039/c7ra08784e
日期:——
Benzylic and allylic alcohols are rendered electrophilic without chemical modification by the use of aluminium triflate as catalyst. The reaction succeeds with alcohol, thiol, carbon and nitrogen nucleophiles. When phenols are employed as nucleophiles, C-alkylation ensues. An advanced application of the method is demonstrated in the synthesis of 2H-chromenes and their N and S analogues.
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
Coupling of alkenes with Fischer-type alkylidene complexes of iron
作者:M. F. Semmelhack、Rui Tamura
DOI:10.1021/ja00360a053
日期:1983.10
On etudie les reactions d'alcenes fonctionnalises avec (CO) n Fe=C(OC 2 H 5 )R (avec R=C 6 H 5 , n-C 4 H 9 , t-C 4 H 9 ). Les reactions ont lieu avec une grande regioselectivite
在研究反应中,d'alcenes 功能化 avec (CO) n Fe=C(OC 2 H 5 )R (avec R=C 6 H 5 , nC 4 H 9 , tC 4 H 9 )。大区域选择性反应
Aluminum Triflate as a Powerful Catalyst for Direct Amination of Alcohols, Including Electron‐Withdrawing Group‐Substituted Benzhydrols
Directaminations of allylic alcohols, benzylic alcohols, and benzhydrols with electron‐withdrawing (F, Br, I, NO2, or CN) substituents were efficiently catalyzed by aluminumtriflate [Al(OTf)3] to afford the corresponding biarylamines in high yield, and the dibromo‐substituted product was further transformed into letrozole.
Water promoted allylic nucleophilic substitution reactions of (<i>E</i>)-1,3 diphenylallyl acetate
作者:Seema A. Ghorpade、Dinesh N. Sawant、Arwa Makki、Nagaiyan Sekar、Jörg Eppinger
DOI:10.1039/c7gc03123h
日期:——
greener protocol for the allylic alkylation, allylic amination, O-allylation of (E)-1,3-diphenylallyl acetate is described. The developed methodology is applicable for a wide range of nucleophiles furnishing excellent yields of corresponding products up to 87% under mild reaction conditions. A distinct effect of water and base is explored for allylicnucleophilicsubstitution reactions of (E)-1,3-diphenylallyl