A series of soluble, non-cross-linked polystyrene-supported triphenylphosphane and 4-dimethylaminopyridine reagents were prepared. Some of these polymeric reagents contained either alkyl alcohol or phenol groups on the polymer backbone. The use of these materials as organocatalysts in a range of Morita-Baylis-Hillman reactions indicated that hydroxyl groups could participate in the reactions and accelerate product formation. In the cases examined, phenol groups were more effective than alkyl alcohol groups for catalyzing the reactions. This article is one of the first reports of the synthesis and use of non-natural, bifunctional polymeric reagents for use in organic synthesis in which both functional groups can cooperatively participate in the catalysis of reactions.

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[reaction: see text] A study of the effect of Michael acceptor stereochemistry on the efficiency of intramolecular Morita-Baylis-Hillman (MBH) reactions has been performed. The reactions were catalyzed by a phosphine, and the reaction substrates studied were enones containing a pendant aldehyde moiety attached at the beta-position of the alkene group. In all cases examined with PPh3 as the catalyst, cyclization substrates possessing (Z)-alkene stereochemistry afforded a much higher yield of the desired product than did the E isomeric substrates under identical reaction conditions. This was also true when a polymer-supported phosphine catalyst was used. While both alkene isomers afforded the same product, in parallel reactions, the Z isomer afforded 2.5-8.5 times higher yield than did the corresponding E isomer. It is proposed that steric effects are a possible source of this dramatic difference in reactivity. Substrates where the beta-substituent is cis to the electron-withdrawing substituent are relatively more accessible to react with the nucleophile catalyst than are their trans counterparts. These findings are expected to be useful in the design of synthetic intermediates, as intramolecular MBH reactions are being increasingly used in the preparation of complex synthetic targets.

Ketones Q 0350Bifunctional Polymeric Organocatalysts and Their Application in the Cooperative Catalysis of Morita-Baylis-Hillman Reactions. -Various soluble, non-cross--linked polystyrene-supported triphenylphosphane and 4-dimethylaminopyridine catalysts are developed. In all reactions, (I) and (II) are the most effective ones showing the crucial role of the hydroxyl groups that can participate in the reactions and accelerate product formation. -(KWONG, C. K.-W.; HUANG, R.; ZHANG, M.; SHI, M.; TOY*, P. H.; Chem. Eur.