Metal catalysts Tsuji-Trost reaction

For further details of this reaction, the reader is referred to Chapter 9. The catalytic allylation with nucleophiles via the formation of Ti-allyl metal intermediates has produced synthetically useful compounds, with the palladium-catalyzed reactions being known as Tsuji-Trost reactions [31]. The reactivity of Ti-allyl-iridium complexes has been widely studied [32] for example, in 1997, Takeuchi idenhfied a [lrCl(cod)]2 catalyst which, when combined with P(OPh)3, promoted the allylic alkylation of allylic esters 74 with sodium diethyl malonate 75 to give branched... 

Several other metal catalysts have been shown to mediate the Tsuji-Trost reaction, with molybdenum being the most developed. Trost first reported the use of molybdenum for allylic alkylation in 1982. The most important aspect of the use of this metal is its regiocomplimentary with the palladium-catalyzed process. While palladium preferentially gives linear adducts (in the absence of electronic bias), molybdenum gives preferentially branched adducts. ... 

In the twentieth century, palladium was the most important metal catalyst in transition metal-catalyzed organic transformations. First, many types of transformations can be catalyzed by a palladium catalyst, including the Heck reaction, the cross-coupling reaction, and the Tsuji-Trost reaction. Second, palladium is extraordinarily tolerant of nearly any type of organic functional group and its high chemoselectivity makes it feasible for use in functionalized or complex systems. Due to these characteristics, palladium is an ideal catalyst in cascade reactions and the total synthesis of natural products. 

The Tsuji-Trost reaction involves the coupling of allyl electrophiles with nucleophiles with a broad range of metal complexes, including those of nickel, palladium, platinum, rhodium, iron, ruthenium, etc (Scheme 13.37). " In a typical example, an allyl acetate or carbonate reacts with a palladium catalyst by displacement of the leaving group to give 7i-allyl palladium complexes that can undergo substitution by a nucleophile. 

Cellulose is a natural biopolymer, which is biodegradable, environmentally safe, widely abundant, inexpensive, and easy to handle [57]. Cellulose and its derivatives are widely used in chemical and bio-chemical applications and also as supports for the synthesis of organic molecules [58]. Interestingly, the cellulose fibers also act as a nanoreactor for the stabilization of metal nanoparticles [59]. However, its use as a support for catalytic applications is not well explored. Recently, Choplin and coworkers reported cellulose as the support for water soluble Pd(OAc>2/5 TPPTS system in the Trost-Tsuji allylic alkylation reaction [60]. To corroborate the above concept in the cross coupling of aryl halides and boronic acids, we reported A-arylation of imidazoles with aryl halides using a cellulose-supported Cu(0) catalyst (CELL-Cu(O) [61]. The prepared catalyst was well characterized using various instrumental techniques. For example, the X-ray diffraction pattern of CELL-Cu(O) catalyst clearly indicates the presence of Cu (111) and Cu (200) phases which are attributed to Cu(0) [46]. Further, the high resolution XPS narrow scan spectrum of the fresh CELL-Cu(O) catalyst shows a Cu 2p3/2 peak at 932.72 ev, which is attributed to Cu (0) [22]. 

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