Pellitorine, synthesis

Pelletierine and associated bases, pharmacological action, 62, 108 isoPelletierine, 55, 57, 58 pserwfoPelletierine, 55, 58 constitution, 59 synthesis, 61 Pellitorine, 2... 

Another useful compound is the 1 2 telomer of malonate and butadiene, 137. The first example is the synthesis of pellitorine (138), a naturally occurring pesticide (126). The terminal double bond was hydrogenated selectively with RuCl2(PPh3)3 as a catalyst. Partial hydrolysis afforded the monoester, which was treated with PhSeSePh to displace one of the carboxyl group with phenylselenyl group. Oxidative removal of the phenylselenyl group afforded 2,4-decadienoate (139), which is converted to pellitorine (138) ... 

Ene reactions of Pummerer-type reaction intermediates have been used as key steps in the synthesis of both pellitorine and trichonine. ... 

Five isobutylamides were isolated as insect growth inhibitors and toxicants from Fagara macrophylla and identified from their spectroscopic and chemical data. Synthesis and bioassay of the five natural products plus four analogs showed pellitorine to be the most active against a variety of insects, but not against a species of snail. 

In 2004, Ley et al. [45] showed a stereoselective enzymatic synthesis of cis-pellitorine [N-isobutyldeca-(2 ,4Z)-dienamide], a taste-active alkamide naturally occurring in tarragon. The reactants were ethyl ( ,Z)-2,4-decadienoate— the pear ester described before—and isobutyl amine. The reaction is catalysed by lipase type B from Candida antarctica (commercially available), which shows a remarkable selectivity towards the 2 ,4Z ester. The yield was about 80%. 

Semple, J. E. A concise synthesis of pellitorine. Organic Preparations and Procedures International 1995, 27, 582-586. 

The same type of coupling, catalyzed by palladium(O), can be carried out using alkenylboronates (generated by hydroboration of acetylenes) and -P-bromoacrylamides [49]. This Suzuki methodology has been used for the synthesis of pellitorine (1), trichonine (13), piperlonguminine (23), piperine (25), dehydropipernonaline (29) and 1-piperettylpyrrolidine (34) [34] (Scheme 6). 

Silylated glutaconaldehyde (36) has been used as a five carbon homologating agent for the synthesis of pellitorine (1) and sarmentine (3) by reaction with w-pentylmagnesium bromide followed by oxidation to the corresponding acid and final amidation [58] (Scheme 14). 

Isomerization reactions of 2-ynoic acids [59] and P-allenic amides [60] also provide suitable methodologies for the preparation of conjugated amides. The former compounds are isomerized by catalysis with ruthenium or iridium complexes and allow the synthesis of pellitorine (1), Achillea amide (4) and trichonine (13) (Scheme 15). 

With respect to the latter strategy, several types of elimination reaction have been described for intermediates having one or two leaving groups in the aliphatic chain. An example is the elimination of the selenoxide derived from an a-phenylselenyl ester to give compound (38), which is then transformed into pellitorine (1) [62] (Scheme 18). The starting diester (37) is obtained by telomerization of butadiene and malonate. The pyrolysis of 2-(phenylsulfinyl)enoates to 2,4-dienoates has also been applied to the synthesis of pellitorine (1) [63]. 

Finally, thermal sulphur dioxide extrusion from c/j,-2,5-disubstituted 2,5-dihydrothiophene 1,1-dioxides, generated by a retro-Diels-Alder reaction, has been used for the synthesis of pellitorine (1) and pipercide (31) [64] (Scheme 19). 

Jacobson s synthesis of pellitorine, 5, (Scheme 1) [20] is based on two sequential Knoevenagel-Doebner condensations, and gives the desired product in a modest overall yield of 3.3%. 

A terse paper by Kaga et al. reports the synthesis of dienamides in moderate yield by palladium-catalyzed coupling of P-bromoacrylamides with alkenyl boronates. (Scheme 13) [138]. Employing alkenyl boronates derived from appropriate alkynes, the strategy was applied to the synthesis of piperlongumine, 36(n=0), piperine, 42, trichonine, 9(n=14), pellitorine, 5, and the trienyl amide, 48. An alkyl boronate, prepared from l-(3, 4 -methylenedioxyphenyl)-l,5-hexadiene, was similarly used for the synthesis of the non-conjugated dienamide, pipernonaline, 46(n=4) (Scheme 13) [138]. 

Synthesis of naturally occurring pellitorine, possessing insecticidal activity Synthesis of a herbicide... 

The dimerization of butadiene is a useful method for the synthesis of various natural products. Pellitorine, which is an insecticidal compound isolated from Amcydkm pyrethrum roots, queen substances, which are well-known honey bee pheromones, ds-dvetone, which is a naturally occurring unique symmetric 17-manbered cyclic ketone, and recifeiolide, which consists of a 12-membered lactone firamwork, can readily be synthesized from butadiene dimers. 

The telomer of malonate and butadiene is a particularly useful starting material. An example is given in Equation (15), which shows another synthesis of the naturally occuring pesticide pellitorine (compare Section 1.1) [15]. 

This strategy has been exploited in the synthesis of variety of naturally occurring compounds such as pheromones and steroids." For example, selective elimination of the aeetate moiety from cyanohydrin derivative 95 was used to prepare key intermediate 96. Diene 96 was subsequently elaborated to pellitorine (97). ... 

---