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Binaphthyldiamino salen-type Zn, Cu, and Co complexes can efficiently catalyze reactions of epoxides with carbon dioxide in the presence of various catalytic amounts of organic bases. The simplest binaphthyldiamino salen-type Zn complex gave the five-membered cyclic carbonate 2 in excellent yield in the presence of triethylamine. A Lewis acid and Lewis base cocatalyzed mechanism is proposed.

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In the presence of catalytic amounts of sodium iodide, triphenylphosphine, and phenol, carbon dioxide can efficiently react with epoxides to give the corresponding five-membered cyclic carbonates in high yields. The mechanism of this reaction was disclosed by (31)P NMR spectroscopic data and deuterium labeling experiments.

In the aza-Baylis-Hillman reaction of N-sulfonated imines (N-arylmethylidene-4-methylbenzenesulfonamides and others) with methyl vinyl ketone, ethyl vinyl ketone, and acrolein, we found that, in the presence of a catalytic amount of chiral phosphine Lewis base such as (R)-2'-diphenylphosphanyl-[1,1']binaphthalenyl-2-ol LB1 (10 mol %) and molecular sieve 4A, the corresponding aza-Baylis-Hillman adducts could be obtained in good yields with good to high ee (70-95% ee) at low temperature (approximately -30 to -20 degrees C) or at room temperature in THF, respectively. In CH2Cl2 upon heating at 40 degrees C, the aza-Baylis-Hillman reaction of N-sulfonated imines with phenyl acrylate or naphthyl acrylate gave the adducts in good to high yields (60-97%) with moderate ee (52-77%). The mechanistic insight has been investigated by 31P and 1H NMR spectroscopic measurements. The key enolate intermediate, which has been stabilized by intramolecular hydrogen bonding, has been observed by 31P and 1H NMR spectroscopy. An effective bifunctional Lewis base and Bronsted acid phosphine Lewis base system has been disclosed in this catalytic, asymmetric aza-Baylis-Hillman reaction.

Novel axially chiral Rh N-heterocyclic carbene complexes were prepared from axially dissymmetric 1,1'-binaphthalenyl-2,2'-diamine and applied in the Rh-catalyzed enantioselective hydrosilylation of methyl ketones. The corresponding sec-alcohols can be obtained in high yields with good to excellent ee.

Gold-catalyzed reactions, which have been widely explored over the past several years, are powerful tools in organic synthesis to access complex molecular frameworks, and some corresponding excellent reviews have been reported. However, little attention has been paid to summarize the reactions of strained small-ring-containing molecules catalyzed by gold. This critical review mainly puts its emphasis on the recent progress in the field of gold-catalyzed transformations of cyclopropyl-, cyclopropenyl-, epoxy- and aziridinyl-containing molecules. The rapid construction of interesting building blocks in organic synthesis from strained small rings catalyzed by gold has been summarized in this review (106 references).

Binaphthyldiamino, ethyldiamino and cyclohexyldiamino Schiff bases can catalyze the reaction of epoxides with carbon dioxide in the presence of catalytic amounts of various organic bases to give the corresponding cyclic carbonates in high yields. The simplest binaphthyldiamino Schiff base, derived from the reaction of binaphthyldiamine with salicylaldehyde, gave the highest yield of cyclic carbonate. This catalytic system can be further simplified by use of a phenol instead of the Schiff base to give the corresponding cyclic carbonates in high yields as well. Mechanistic insights were obtained based on a deuterium labeling experiment. The reaction of aziridines with CO2 and epoxide with CS2 were also examined under the same reaction conditions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)