The development of a new method for the enantioselective synthesis of disubstituted g-butyrolactones is reported. Based on this strategy, the total synthesis of three paraconic acids, that is (À)-roccellaric acid, (À)-nephrosteranic acid and (À)-protopraesorediosic acid, and the formal total synthesis of (À)-methylenolactocin and (À)-protolichesterinic acid is described, which are important because of their antibiotic and antitumor properties. Key steps of the synthesis are copper(i)-catalyzed asymmetric cyclopropanations of furans, highly diastereoselective Sakurai allylations, Lewis acid or Lewis base catalyzed retroaldol/lactonization cascades, and ruthenium(ii)-catalyzed, intermolecular cross metathesis reactions.

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Palladium-Catalyzed Asymmetric Synthesis of Axially Chiral Allenylsilanes and Their Application to SE2' Chirality Transfer Reactions. -The desilylative SE2' reactions of the axially chiral allenylsilanes proceed with complete transfer of the chirality to the newly formed tertiary and quaternary stereocenters of the resulting propargylic derivatives. -(OGASAWARA*, M.; OKADA, A.; SUBBARAYAN, V.; SOERGEL, S.; TAKAHASHI, T.; Org. Lett. 12 (2010) 24, 5736-5739, http://dx.

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