Palladium-catalysed exchange of allylic groups of ethers and esters with active-hydrogen compounds

Abstract

The allylic groups of ethers and esters exchange with a variety of active hydrogen compounds in the presence of palladium catalysts.IN the degradation of octa-Z,7-dienyl phenyl ether to phenol and octa-1,3,7-triene with a palladium catalyst,l Smutny observed the formation of a small amount of 2and 4-(octa-2,7-dienyl)phenol,2 which is obviously not formed via a normal or abnormal Claisen rearrangement of the ether.We find that the octadienyl group of octa-2,7-dienyl phenyl ether exchanges with a variety of active-hydrogen compounds in the presence of palladium catalysts, and further research has led to the finding that the allylic compounds (I) react with active-hydrogen compounds to give allylic derivatives of the active-hydrogen compounds R10-CH2CH = CHR2

The preparation of amino sugars and branched-chain sugars by palladium-catalyzed, allylic substitution of alkyl hex-2-enopyranosides

“…methods for the synthesis of unusual amino, deoxy, As Our chief substrate for an the unsaturated, and branched-chain sugars (2), we de-utility of the method in the carbohydrate field,[ we cided to examine whether the palladium-catalyzed chose the crystalline ethyl 4,6-di-0-acetyl-2,3-disubstitution of allylic acetates by amines or reac-de0xy-cr-~-er~thro-hex-2-eno~~ranoside (I). his tive methylene compounds (3)(4)(5)(6) might be em-compound is readily prepared (9) from commerplayed to advantage in carbohydrate chemistry. In c i a l l~ available D-glucal tfiacetate-For some anthis reaction, which represents one of the numer-cillary experiments, to be performed in the hope of ous applications of organopalladium chemistry (7) that are currently in widespread use, an allylic 'To our knowledge, only one organopalladiurn reaction (of a acetate in the presence of a catalyst such as tet-different kind) with carbohydrates has been previously studied.…”

Production of Csp3–Csp3 Bonds through Palladium‐Catalyzed Tsuji–Trost‐Type Reactions of (Hetero)Benzylic Substrates

“…[20] This allylpalladium complex could be reduced by addition of the malonate anion to its allyl unit, liberating the Pd 0 catalyst, which would be prevented from aggregation by cod. [21] As exemplified by the results shown in Equation (5) 2 and Pd(dba) 2 leading to low levels of conversion. Various aryl carbonates and nucleophilic species were coupled under the optimum conditions [Equation (6)].…”

“…[5] Under these conditions, lower yields were obtained in THF, MeCN, N,N′-dimethylpropyleneurea, and dioxane. [18] Various catalytic systems were tested in THF: switching either from Pd(dba) 2 to Pd(OAc) 2 or from DPPE to PPh 3 led to ineffective reactions. -Hydride elimination was detected from methyl 1-(naphthalen-2-yl)ethyl carbonates [Equation (3)].…”

“…[1] Initially reported in 1970, [2,3] this catalytic reaction has led to a plethora of papers and synthetic applications. [4] It was only more than 20 years later that Legros and Fiaud disclosed the first addition of carbonucleophiles to cationic η 3 -benzylpalladium intermediates.…”

Recollections of organopalladium chemistry

“…Later, based on Pd-catalyzed reversible exchange reaction of allylic esters, catalytic allylation of nucleophiles with allyl acetate (11) and allyl phenyl ether shown below was reported by two groups in 1970 (Scheme 7) [7].…”