Biocatalytic preparation of bicyclo[3.2.0]heptane derivatives

Enantiomerically Pure Cyclobutane Derivatives and Their Use in Organic Synthesis

“…Lipases can even tolerate unnatural substrates such as cyclobutanol esters having a β-chloro substituent. 174 The resolution of cyclobutanols by lipasecatalyzed esterification has been used in the preparation of optically pure cyclobutanes. 175 The racemic alcohol 223 can be resolved using lipase-mediated acetylation with vinyl acetate (Scheme 81).…”

“…It is interesting to note that the corresponding cyclobutanones of 219 and 221 are poor substrates for the hydrolysis. Lipases can even tolerate unnatural substrates such as cyclobutanol esters having a β-chloro substituent . The resolution of cyclobutanols by lipase-catalyzed esterification has been used in the preparation of optically pure cyclobutanes …”

Enantioselective hydrolyses with Yarrowia lipolytica: a versatile strain for esters, enol esters, epoxides, and lactones

“…The yield of the reaction on analytical scale was determined by GC using 4methylcyclohexanone as internal standard. The absolute configurations of the compounds were determined comparing the sign of their specific rotation with those of the literature: for (1S,5R,6S)-1 23 [h] D = −36.3 (c 2.27, CHCl 3 ); for (1R,5S,6R)-10 24 [h] D =−68 (c 1.1, CHCl 3 ); for (1R,2S)-2 25 [h] D =−37.4 (c 1.50, CHCl 3 ); for (1S,2R)-11 26 [h] D =18 (c 1.0, MeOH); for (1S,2S)-3 27 [h] D =69.9 (c 0.64, EtOH); for (1R,2R)-12 28 [h] D =−38.2 (c 9.6, EtOH); for (R)-13 26 [h] D =14 (c 0.23, MeOH); for (S)-16 28 h D =−17 (neat); for (S)-7 29 h D =−33 (neat); for (R)-8 30 [h] D =21.2 (c 8.6, EtOH). The absolute configurations of compounds 9 31 and 14 32 were assigned comparing the signs of their specific rotation with those of the literature: (R)-(−)-9 and (R)-(−)-14.…”

Potentially useful lipase-catalysed transesterifications

“…Steroselective hydrolysis, catalysed by CCL of 2,6-diacetoxybicyclo [3"3"1] nonane gives (+)-(IS, 2R, 5S, 6R)-6-acetoxybicyclo [3"3.1 ] nonane-2-ol and (-)-(1 R, 2S, 5R, 6S)-2,6-diacetaxybicyclo 1-3"3-1] nonane, which are used in the synthesis of optically active crown ethers and podands (Naemura et al 1989). Bicyclo [3"2.0] hept-2-en-6-ols, central building blocks for the synthesis of chiral cyclobutane and cyclopentane systems have been prepared using CCL and PFL with > 99~ ee by the resolution of their acetates and/or butyrates (Klempier et al 1990). 6-Acetoxy-7,7-disubstituted bicyclo [3.2"0] hept-2-ene is enantioselectively hydrolysed by PPL, CCL and Pseudomonas cepacia lipase to yield (R)-alcohol regardless of the configuration of the main framework of the substrate.…”