Hydrogen-bond (HB)-donor catalysts that bear a 2-aminoquinazolin-4-(1H)-one or a 3-aminobenzothiadiazine-1,1-dioxide skeleton have been developed, and it has been shown that these catalyst motifs act similarly to other HB-donor catalysts such as thioureas. The highly enantioselective hydrazination of 1,3-dicarbonyl compounds was realized even at room temperature with up to 96% ee for 2-aminoquinazolin-4-(1H)-one-type catalysts, which were more effective than the corresponding urea and thiourea catalysts. In addition, benzothiadiazine-1,1-dioxide-type catalysts were shown to promote the isomerization of alkynoates to allenoates with high enantioselectivity. To overcome the problem that the products were obtained as mixtures with the starting alkynoates, we developed the tandem isomerization and cycloaddition of alkynoates for the synthesis of advanced chiral compounds such as bicyclo[2.2.1]heptenes and 3-alkylidene pyrrolidine without a significant loss of enantioselectivity.

The left hand claps the right: Highly enantioselective isomerization of racemic α‐substituted alkynoates into nonracemic trisubstituted allenoates was achieved through the catalytic dynamic kinetic resolution mediated by bifunctional benzothiadiazine. This reaction proceeded with good conversion and high enantioselectivity to give the desired allenoates in good yields without recovering the significant amounts of starting materials.

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Organocatalyzed Isomerization of α-Substituted Alkynoates into Trisubstituted Allenoates by Dynamic Kinetic Resolution. -The isomerization of alkynoates is smoothly catalyzed by a bicyclic guanidine-diamine catalyst to afford the trisubstituted allenoates (II) in high enantioselectivities (up to 94% e.e.). The reaction proceeds with epimerization of the starting alkynoate and, thus, allows for higher chemical yields as compared to previously described isomerization reactions. Additionally, the α-substituent at the allenoate suppresses the reverse isomerization. -(INOKUMA, T.; FURUKAWA, M.; SUZUKI, Y.; KIMACHI, T.; KOBAYASHI, Y.; TAKEMOTO*, Y.; ChemCatChem 4 (2012) 7, 983-985, http://dx.doi.org/10.1002/cctc.201200065 ; Grad. Sch. Pharm. Sci., Kyoto Univ., Sakyo, Kyoto 606, Japan; Eng.) -Mischke 42-063

Organocatalysis. -The catalysts (I)-(III) are shown to be effective in various reactions. Enantioenriched allenes mostly cannot be separated from the substrates. -(INOKUMA, T.; FURUKAWA, M.; UNO, T.; SUZUKI, Y.; YOSHIDA, K.; YANO, Y.; MATSUZAKI, K.; TAKEMOTO*, Y.; Chem. Eur.