A simple and efficient synthesis of enantiomeric (3aRS,4RS,6aSR)-4-hydroxy-3,3a,4,6a-tetrahydro-1H-cyclopenta[c]furan-1-ones

A New Approach to the Synthesis of Chiral Blocks for Cyclopentanoids

“…A better result -absolute regioselectivity of the epoxide ring-opening by the action of PhSwas obtained in the case of anti-epoxylactones (-)-16 and (+)-16. Compound (+)-23 is a suitable synthetic precursor for entecavir [7,38].…”

“…The next form of bicycles, which was tested in a similar optical resolution via a diastereomeric pair, was adduct 40 [7] (Figure 19). Key steps of the approach are: a) easy cleavage of dichlorocyclobutanone cycle 40 by treatment with a chiral auxiliary (+)-α-methylbenzylamine with the formation of a mixture of diastereomeric amides 41; b) transformation of these amides into bicyclic aminals 42, which can be easily separated by column chromatography on silica gel.…”

“…For conversion of the gem-dichloromethyl group of compound 3 into an aldehyde, inexpensive reagents were applied (FeCl 3 •6H 2 O, BaO or NaHCO 3 ) [15]. With the use in the hydrolysis of catalytic amounts of PdCl 2 , the expected compounds (5) quickly formed products of intermolecular self-condensation (7). The ether formation was also found after evaporation of solutions of individual compounds 7a and 7b under reduced pressure and by heating to 60°C (Figure 4).…”

“…In the synthesis of natural and unnatural biologically active cyclopentanoids, the preparation of chiral orthogonally functionalized cyclopentane (cyclopentene) block-synthons is important. They are required in the synthesis of monocyclic cyclopentanoids (prostaglandins, carbanucleosides, pheromones, cyclopentenone antibiotics) as well as in approaches to the more complex bi-and polycyclic compounds containing a fragment of the cyclopentane ring (brefeldin А, hitachimycin, didemenones, hybridalactone, retigeranic acid, quadrone, ginkgolide) [7].…”

New chiral block for cyclopentanoids synthesis

“…The synthesis of enantiomerically pure bicyclic compound 3 we described in [7]. One of possible versions of using compound 3 for the preparation of chiral cyclopentanoids is utilizing the potential of allylsilane fragment, in particular, the substitution of the silane group via S E 2' mechanism [8,9].…”