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Preparation of Synthetically Useful Chiral Building Blocks - 5-Alkylated gamma-Lactones via Catalytic Asymmetric Hydrogenation of4-Oxo Esters

100%

Juszkiewicz G. , Asztemborska M. , Jurczak J.

Polish Journal of Chemistry

2002

tom Vol. 76 / nr 12

1707-1711

Asymmetric hydrogenation of 4-oxo esters, catalyzed by cationic BINAP-Ru(II) complexes, afforded in a good overall yield and with excellent enantioselectivity (> 98% ee), the respective 5-alkylated -lactones, useful intermediates for the preparation of pheromones.

Synteza γ-laktonów z podstawnikami aromatycznymi

58%

Skrobiszewski A. , Gładkowski W.

Wiadomości Chemiczne

2013

tom [Z] 67, 9-10

943--960

Biological activities of lactones are predominantly determined by different substituents on a lactone ring. γ-Lactones with aromatic substituents have interesting biological activities and serve as useful intermediates in the synthesis of many natural and synthetic products. Pulvinic and vulpinic acids exhibit antimicrobial, antioxidant and anticancer activity [1–3]. Paraconic acids have anticancer and antibacterial activity [4, 5]. The interesting biological activities i.a. antileukemic, anti- HIV and cytostatic, have been found for dibenzyl-γ-lactones [8]. This review covers some examples of synthetic and biotechnological methods leading to either racemic or optically active γ-lactones with aromatic substituents. The racemic α-benzylidene lactones can be produced from Baylis-Hillman acetates [9]. The multicomponent synthesis of the paraconic acid analogs is performed by a fourfold metallation-conjugate addition-aldol addition-intramolecular transesterification sequence [4]. Suzuki-Miyaura reaction is the key step in the synthesis of asymmetric pulvinic acids [1]. Some other examples of synthetic strategies involving the reactivity of ylides, vicinal dianions, ozonolysis or Claisen rearrangement are also presented [10–13]. Production of optically active γ-lactones with aromatic substituents involves application of biotechnological and chemical methods. The first one includes using commercially available enzymes [16, 17] or whole cells of microorganisms [18–20]. Chemical methods involve application of chiral starting materials like malic acid esters or the derivatives of succinic acid [14, 15] or chiral catalysts like BINAP-Rh or Ru complexes [7].