A very simple method was developed for the direct, palladium-free catalytic a-allylic alkylation of aldehydes. The direct organocatalytic intermolecular a-allylic alkylation reaction was mediated by a simple combination of Brønsted acid and enamine catalysis which furnished a-allylic alkylated aldehydes and cyclohexanone in high yields and chemoselectivities. The reaction conditions are mild and environmental friendly, the process is conducted under an atmosphere of air without the need for dried solvents, and water is the only side product of the allylic alkylation reaction.

A practical and asymmetric process for the total synthesis of (+)-biotin (1) has been accomplished starting from cis-1,3-dibenzyl-2-oxoimidazolidine-4,5-dicarboxylic acid (2). This approach features a highly enantioselective alcoholysis of mesocyclic anhydride 3 into (4S,5R)-cinnamyl hemiester 4 mediated by Cinchona alkaloids. Another attractive feature of this synthesis involves the use of recyclable palladium nanoparticles-catalyzed assembly of the 4-carboxybutyl chain at C-4 in (3aS,6aR)-thiolactone 7 employing an improved Fukuyamatype cross-coupling reaction

A highly enantioselective Friedel-Crafts alkylation of indoles with α,β-unsaturated aldehydes with excellent enantioselectivities (up to Ͼ99 % ee) has been developed, and this improved method offers substantial advantages over traditional approaches, not only by avoiding the use of acids or bases, but also in terms of the higher level of stereoselectivity. In addition, we have demonstrated through a plausible

This improved method offers substantial advantages over traditional approaches such as avoiding the use of acids or bases and the high level of stereoselectivity.

Dual Amine-and Broensted Acid-Catalyzed α-Allylic Alkylation of Aldehydes. -A simple and palladium-free, catalytic variant of title reaction is conducted under air without the need for dried solvents; water is the only side product of the reaction. The use of enantiomerically pure amine catalysts induces only poor enantioselectivities (up to 7% e.e.). -(XU*, L.-W.; GAO, G.; GU, F.-L.; SHENG, H.; LI, L.; LAI, G.-Q.; JIANG, J.-X.; Adv.