Allylic substitution of meso-1,4-diacetoxycycloalkenes in water with an amphiphilic resin-supported chiral palladium complex
Asymmetric π-allylic substitution of meso-1,4-diacet-oxycyclopentene and meso-1,4-diacetoxycyclohexene with various nucleophiles was performed with an amphiphilic polystyrene-polyethylene glycol) (PS-PEG) resin-supported chiral imidazoin-dolephosphine-palladium complex in water as a single reaction medium under heterogeneous conditions to give the corresponding 1-acetoxy-4-substituted cycloalkenes with up to 99% ee.
Synthesis of optically active cyclopenta[b]benzofuran as a precursor of m-phenyleneprostacyclin
The optically pure cyclopenta[b]benzofuran derivatives (-)-1 and (-)-2 were synthesized from (+)-(1S,4R)-cis-4-acetoxy-2-cyclopenten-1-ol [(+)-3] via sequential Mitsunobu reaction and palladium-catalyzed allylic substitution with phenol derivatives followed by SN2′ intramolecular cyclization.
Chemoenzymatic synthesis of a versatile cyclopentenone: (+)-(3aS,6aS)-2,2-dimethyl-3aβ,6aβ-dihydro-4H-cyclopenta-1,3-dioxol- 4-one
The title cyclopentenone has been prepared by enzymatic resolution of cis-4-phenyloxy- and cis-4-(4-methoxyphenyloxy)-cyclopent-2-en-1-ol in isopropenyl acetate using Pseudomonas cepacia lipase. The use of a 4-methoxyphenyloxy-alcohol intermediate enabled the use of both enzymatically resolved enantiomers in the synthesis of the desired (+)-enone.
Biadatti, Thibaud,Esker, John L.,Johnson, Carl R.
p. 2313 - 2320
(2007/10/03)
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