10-Undecenal synthesis

The stereocontrolled synthesis of a chiral, polyhydroxy 1,7-dioxa-spiro[5.5]undecene from 2,3,4,6-tetra-O-benzyl-D-glucono-1,5-lactone... 

Majetich reports a general intramolecular Lewis acid allylation protocol for the synthesis of bicy-clo[5.4.0]undecen-3-ones (168) and bicyclo[4.4.0]decen-3-ones (170), which are 1,6-addition products (Scheme 27). The same precursors, (167) and (169), when submitted to the fluoride ion cyclization protocol, also afford 1,2- and 1,4-addition products.73 Typically, ethylaluminum dichloride, a proton sponge Lewis acid, is used in order to minimize adventitious protonic desilylation. Other 0,y-unsatu-rated silanes also undergo similar intramolecular Lewis acid catalyzed additions for example, the si-lylpropargylic enones (171) undergo intramolecular cyclization to the allenylspiro system (172).74... 

The first synthesis of 3-sila-l,2,4-trioxepane 208 was achieved by a two-step procedure involving initial ozonolysis of undecen-4-ol followed by bissilylation with BuSiSiOTf) , in the presence of imidazole (Equation 39). Compound 208 was separated by flash chromatography in 45% yield. Alkylation of 208 with alkyltrimethylsilane in the presence of SnCU gave alkylated silatrioxepane 209 in 5% yield <2005T4657>. 

The most attractive method for production of pure 9,ll-c,t-CLA is through the dehydration of ricinoleic acid. Synthesis from this relatively inexpensive starting material has proven elusive as it is difficult to control the formation of dehydration products (124). Synthesis of 9,ll-c,t-CLA from ricinoleic acid has been reported (125), which, although an efficient reaction, uses expensive elimination reagents such as l,8-diazobicyclo-(5,4,0)-undecene. For most applications, the high cost of the elimination reagent increases the production cost beyond the level at which commercial production of CLA is economically viable. 

In the presence of 3-8 mol equiv. of pyridine as ligand (compared with Co) the phenomenon of ligand-accelerated catalysis [8] is observed with higher activity and improved selectivity of the catalyst system [9]. The cobaltcarbonyl/ pyridine catalyst system is applied industrially for the synthesis of higher alkanoic acids, e.g., the hydrocarboxylation of isomers of undecene yields dodecanoic acid with approximately 80% selectivity [10],... 

Takei has completed a synthesis of A26771B in a manner reminiscent of Ease s work (Scheme 2.3). The synthesis begins with the addition of methyl lithium to 10-undecenal (24) and acetylation of the resulting alcohol to give 25... 

Dimedone provides diazo dimedone (135) with -benzoic acid sulfonylazide (84%) and with p-tolyl sulfonylazide (96%). Weak nucleophilic base such as 1,8-diazabicyclo[5.4.0]undecen-7-ene (DBU) has been used as catalyst for the diazo transfer reactions of 1,3-diketones (136 -139).55 A highly efficient methodology in solid state has been developed for the synthesis of a-diazo carbonyl/sulfonyl compounds from 1,3-diketones using tosyl azide. This method avoids any aqueous workup and diazo compounds are obtained via a column filtration over silica gel. 0... 

The first synthesis for methyl (Z)-2-methoxy-6-hexadecenoate was reported by Soderquist et al. [35]. The idea behind the construction of the a-methoxy functionality was the addition of a carboxy synthon to the corresponding aldehyde, in this case 5- pentadecenal, followed by methylation of the hydroxy group. This synthesis started with the Suzuki-Miyaura cross coupling of 4-bromo-l-butyl-9-borabicyclononane with (Z)-l-bromo-l-undecene, prepared as shown in Fig. (11). 

Intramolecular ester condensation. Indian chemists have synthesized 2-(6 -methoxycarbonylhexyl)cyclopentene-2-one-l (4) from methyl 10-undecene-oate (1). The enone has been used for synthesis of prostaglandins. 

Synthesis of olefins This organolithium reagent undergoes coupling with 1-iodooctane or 1-bromooctane in THF at 25° (1.7 hr.) to give (E)-2-undecene in high yield ... 

Ziegler—Natta polymerizations of aluminate-pro-tected alcohols have also been reported. Shell patented a synthesis of film-forming poly (10-undecen-... 

E)-AIkenes. The preparation and use of this cuprate is exemplified by a synthesis of (E)-2-undecene (equation I). An alternative preparation is the reaction of (E)-propenyliithium directly with 1-iodooctane in about the same yield. ... 

C.-H. Lin and C.-S. Hsu. Synthesis and characterization of cholesteric liquid crystalline copolysiloxanes containing 4-biphenyl 4-allyloxybenzoate and [S]-l-(2-naphthyl)ethyl 6-[4-(10-undecen-l-yloxy) biphenyl-4 -carbon-yloxy]-2-naphthoate side groups. J. Polym. Res., 7 167-173, 2000. 

Huang, Y, Yang, K., and Dong, J.-Y. 2006. Copolymerization of ethylene and 10-undecen-l-ol using a montmoriUonite-intercalated metallocene catalyst Synthesis of polyethylene/ montmorillonite nanocomposites with enhanced structural stability. Macromolecular Rapid Communications 27 1278-1283. 

Another recent study on polyester synthesis through thiol-ene reactions for preparation of monomers from fatty-acid derivatives was described by Pang and co-workers [16]. Authors adopted the same approach for preparing aliphatic diols and diester from 10-undecen-l-ol, methyl 10-undecenoate and thiols. In parallel, they prepared aromatic diesters from methyl vanillate and a series of thermoplastic polyesters were synthesised by polycondensation of the diols and diesters using conventional transesterification methods. These materials were obtained with Mn values of 12-27 kDa and T values of -13 to 13 °C. 

An interesting study on the synthesis of polyethylene (PE) mimics derived from fatty-acid derivatives and thiol-ene polymerisation [39] involved preparation of two different diene monomers from a commercially available derivative of undecenoic acid, 11-bromo-l-undecene, and 10-undecenol for the synthesis of a series of non-biodegradable polymers (Scheme 6.13). The authors considered these non-biodegradable polymers to be renewable plant oil-derived substitutes for PE. 

The research team of Cramail also carried out a pol) hioether synthesis but used a different approach. They undertook the synthesis of AB-type monomers and then polymerised them via the thiol-ene click reaction [41, 42]. The work consisted of the synthesis of 10-undecene-l-thiol from 10-undecenoic acid. Photochemical or thermal initiations were tested for self-polymerisation of this AB monomer, and also by varying the reaction time. Polymers with Mn = 15-40 kDa were obtained and oxidised further, leading to materials with an increased T [21]. 

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