2- -2-alkenoate 5-alken

Many Pseudomonas strains accumulate MCL-PHAs from alkane, alkene, al-kanoate, alkenoate, or alkanol [5,6,14,96]. The composition of the PHAs formed by the pseudomonads of the rRNA homology group I is directly related to the structure of the carbon substrate used [6]. These results suggested that MCL-PHAs are synthesized from the intermediates of the fatty acid oxidation pathway. In almost all pseudomonads belonging to the rRNA homology group I except Pseudomonas oleovorans, MCL-PHA can also be synthesized from acetyl-CoA through de novo fatty acid synthetic pathway [97]. The -oxidation pathway and de novo fatty acid synthetic pathway function independently in PHA biosynthesis. 

The influence of electronic factors on the regioselective cycloadditions of nitrones (551), and (583) to (585) to acrylates has been demonstrated by using dipolarophiles with electrophilic substituents at the P-carbon of the alkene in y-bromo a, 3-unsaturated esters and lactones (774) and in ethyl 2-hydroperfluoro-2-alkenoates (586) (775). The reactions of enoates (586) with nitrones are regio-specific and afford isoxazolidines with the CC>2Et and R/, groups in C-4 and C-5... 

Studies of the transfer of Br+ and I+ from amine-coordinated halonium ions to acceptor l-co-alkenols have been undertaken to determine the mechanism in an effort to assist in the development of chiral transfer reagents. Transfer of Br+ and I+ from two commercially available dimeric hydroquinine and hydroquinidine ligands ((DHQ)2PHAL and (DHQD)2PHAL) to various 1, (o-alkenols and l,co-alkenoic acids is shown to provide enantiomeric excesses of 4-47% depending on the acceptor alkene. 

With respect to the biosynthesis of the solvents it has been speculated on the basis of quantitative data and the identification of (3,y-unsaturated acids in primitive oxytelid beetles that pairs of 1-alkenes and y-lactones are synthesized from corresponding 3-alkenoic acids by either lactonization or by decarboxylation [118]. 

The intramolecular reaction of alkenes with various O and N functional groups offers useful synthetic methods for heterocycles[l3,14,166]. The reaction of unsaturated carboxylic acids affords lactones by either exo- or endo-cyclization depending on the positions of the double bond. The reaction of sodium salts of the 3-alkenoic acid 143 and 4-alkenoic acid 144 with Li2PdCU affords mostly five-membcrcd lactones in 30-40% yields[ 167]. Both 5-hexe-noic acid (145) and 4-hexenoic acid (146) are converted to five- or six-mem-bered lactones depending on the solvents and bases[168]. Conjugated 2,4-pentadienoic acid (147) is cyclized with Li2PdCl4 to give 2-pyrone (148) in water[169]. 

RC02R (all alkano-lides), 2-alken-l-one, 2-alkenoate ester, 2-alkenenitrile (all 2-cyclopente-nones)... 

TL 27 5509 (1986) (3-sulfinyl-2-aUcenoate ester) 28 107 (1987) (3-sulfinyl-2-alkenoate ester) 30 3853 (2-suiiinyI-2-a]ken-l-oiie)l 4003 (sulfinyl quinone), 4227 (fumaric diamide), 6973 (2-alkoxycarbonyl-2-alkene-4-lactam), 6977 (2-alkoxycarbonyl-2-alkene-4-lactam) (1989) 32 947 (sulfinyl maleate), 2005 (2-acyl-2-alkenoate ester), 7751 (4-aIkoxy-3-sulfonyl-2-alken-4-olide) (1991)... 

JOC 56 1983 (1991) (sulfinyl maleimide) 574664 (2-cyano-2-alkenoate ester), 6870 (sulfinyl quinone) (1992) 59 1499 (sulfinyl maleate), 2211 (l-nitro-2-suIfinyl-l-alkene), 7774 (2-cyano-2-alkenoate ester) (1994) 60 4962 (1995) (1,1-disuMmyl-l-aIkene)... 

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