Reversal of stereoselection in diastereodivergence of meso-dicarboxylic anhydrides

Stereoselective Anhydride Openings

“…Kunieda achieved high diastereoselectivity in the ring opening of a variety of bi- and tricyclic anhydrides using lithium complexes generated in situ from various sterically hindered chiral N -sulfonylamino alcohols (Table ) . A significant increase in the diastereoselectivity was observed when hexamethylphosphoric triamide (HMPA) was employed as additive.…”

Asymmetric Alcoholysis of Cyclic Anhydrides

“…More recently, Kunieda attained extraordinarily high diastereoselectivity in the ring opening of a variety of bi- and tricyclic succinic anhydrides with the lithium or zinc salts of rigid chiral N -sulfonyl amino alcohols (Table ) . The steric bulk of the sulfonyl group, the metal species used, and the use of additives all play a crucial role in determining the stereoselectivity.…”

Cinchona alkaloid derivative modified Fe3O4 nanoparticles for enantioselective ring opening of meso-cyclic anhydrides

“…For example, Seebach developed chiral diisopropoxytitanium TADDOLate (a,a,a 0 ,a 0 -tetraaryl-1,3dioxolane-4,5-dimethanol) systems ( 7), 18,19 Shibasaki developed a Ni 2 -Schiff base catalyst (8), 20 and Kunieda developed Li complexes of chiral N-sulphonyl amino alcohols (9). 21,22 However, they are all costly, required in high mol%, and not equally effective for the ring-opening of all kinds of anhydrides (like mono-, bi-and tricyclic anhydrides). Naturally occurring cinchona alkaloids and their derivatives are widely studied for this purpose.…”

“…(1S,2R,3S,4R)-3-(methoxycarbonyl)bicyclo[2.2.1]hept-5-ene-2carboxylic acid (22) was obtained from the Fe 3 O 4 @mQD NP catalyzed methanolysis of anhydride in 91% yield as a white solid and in 98% ee as determined by HPLC analysis of the diastereomeric mixture of the corresponding amide-ester prepared as described above (Hypersil, 20 : 1, hexanes : IPA, 0.5 mL min À1 ), t(major) = 18.09 min, t(minor) = 14.81 min); [a] 25 D (+ 7.2 (c = 4.23, CCl 4 ), literature: 29 [a] 25 D + 7.8 (c = 4.23, CCl 4 ) % for ee: 99%; 1 H NMR (300 MHz, CDCl 3 ): d 1.33 (bd, J = 9.0 Hz, 1H), 1.50 (dt, J = 9.0 Hz and J = 1.8 Hz, 1H), 3.16-3.36 (m, 4H), 3.59 (s, 3H), 6.22 (dd, J = 5.0 and 3.0 Hz, 1H) 6.26 (dd, J = 5.0 and 3.0 Hz, 1H), 6.23 (br s, 1H). 13 (1R,6S)-6-(methoxycarbonyl)cyclohex-3-ene-1-carboxylic acid (24) was obtained from the Fe 3 O 4 @mQD NP catalyzed methanolysis of anhydride in 97% yield as a colourless oil and in 96% ee as determined by HPLC analysis of the diastereomeric mixture of the corresponding amide-ester prepared as described above (Hypersil, 20 : 1, hexanes : IPA, 0.5 mL min À1 , t(major) = 10.83 min, t(minor) = 9.23 min); 1 H NMR (300 MHz, CDCl 3 ): d 2.32-2.41 (m, 2H), 2.54-2.63 (m, 2H), 3.03-3.11 (m, 2H), 3.70 (s, 3H), 5.68 (AB-system, J = 1.7 Hz, 2H), 7.62 (br s, 1H).…”

“…42, 45.56, 45.86, 47.45, 47.54, 66.77, 128.21, 128.33, 128.56, 135.78, 137.94, 138.10, 173.29, 179.93. (22) in the mini-pilot plant Methanol (32.0 g) was added dropwise to a stirred suspension of cis-5-norbornene-endo-2,3-dicarboxylic anhydride (16.4 g) and Fe 3 O 4 @mQD NPs (10.0 g) in diethyl ether (5000 mL) at À45 1C under argon. The reaction mixture was stirred at this temperature for 60 h. During this period, the anhydride gradually dissolved.…”