Synthesis of unsaturated dibasic acid esters from five-, six-, and seven-membered cycloalkanones

Abstract

A new route to diesters of symmetrical octene , decene , and dodecenedioic acids was proposed. The ratio of the cis/trans isomers was 1 : 4. The synthesis involved oxidative splitting of five , six , and seven membered cycloalkanones with hydrogen peroxide into the corresponding ω alkenoic acids followed by esterification and metathesis over Re

How an early or late transition state impacts the stereoselectivity of tetrahydropyran formation by intramolecular oxa-Michael addition

“…Finally, access to the substrates for the 2,3-pattern were obtained by oxidative ring opening of 4-phenylcyclohexanone (Scheme 8). 14 This yielded 4-phenylhex-5-enoic acid which could be reduced to the alcohol 16a. Cross metathesis of alcohol 16a with methyl acrylate yielded ester 17a without any problems, despite the extra hindrance at the allylic position.…”

An Efficient Synthesis of Chiral Non‐Racemic Hydroxyalkanoic Acids by Olefin Cross‐Metathesis Reactions

“…Due to these results also alcohols 1 a,b and esters 2 can be categorized as Type I olefins . Homodimer 3 a was present exclusively as ( E )‐ 3 a , while 3 b , 5 a and 5 b were isolated as E / Z mixtures, with ratios 1.5:1, 8:1 and 7:1, respectively. The allylic alcohol 1 a resulted to be a better CM substrate than the homoallylic alcohol 1 b since ( E )‐ 4 a was isolated in good yield (41%), being easily separated from homodimers 3 a and 5 b .…”

“…The assignment of the E and Z configurations of compounds 3 a‐d , 4 a‐d and 5 a,b was made by means of 13 C‐NMR. For compounds 3 a , 5 a and 5 b the stereochemistry was assigned by comparison with literature 13 C‐NMR data. The difference of 13 C chemical shifts of the olefinic and allylic carbon atoms of Z and E isomers (Δ=δ Z ‐δ E ) for compounds 3 b‐d , 4 b , d and 5 a,b , diagnostic for the configuration assignment, occurred in the range of –0.5÷–1.38 and –5.20÷–5.73 ppm, respectively, as reported in Table S (Supporting information).…”

Synthesis of an Advanced Intermediate of the Macrotricyclic Core of Roseophilin

“…Herein, we report our approach to the synthesis of 8, which was realized in six steps and >10% overall yield starting from a TFAA-mediated regioselective acylation of N-tosylpyrrole previously developed by one of us. 5 As shown in Scheme 2, acylation of N-tosylpyrrole with 6-heptenoic acid 6 in the presence of TFAA, followed by reduction of the carbonyl group in the acylation product with borane-tert-butylamine complex in the presence of aluminum trichloride 7 delivered 4 in 37% isolated yield over two steps. A second acylation with monomethyl malonate and TFAA gave acylpyrrole 5 8 in 61% yield.…”