Herein we report the first highly enantioselective allenoate-Claisen rearrangement using doubly axially chiral phosphate sodium salts as catalysts. This synthetic method provides access to β-amino acid derivatives with vicinal stereocenters in up to 95% ee. We also investigated the mechanism of enantioinduction by transition state (TS) computations with DFT as well as statistical modeling of the relationship between selectivity and the molecular features of both the catalyst and substrate. The mutual interactions of charge-separated regions in both the zwitterionic intermediate generated by reaction of an amine to the allenoate and the Na +salt of the chiral phosphate leads to an orientation of the TS in the catalytic pocket that maximizes favorable noncovalent interactions. Crucial arene−arene interactions at the periphery of the catalyst lead to a differentiation of the TS diastereomers. These interactions were interrogated using DFT calculations and validated through statistical modeling of parameters describing noncovalent interactions.

An efficient synthesis of (E)-5-aryl(halo)methylenebicyclo[2.2.2]oct-2-enes is reported. Lewis acid-promoted carbohalogenation of 4-(3-arylprop-2-ynyl)-cyclohex-2-enols in dichloromethane proceeds rapidly to afford the exo-methylenebridged bicycles in good yields. This method also provides an easy access to (E)-5-aryl(halo)methyl-A C H T U N G T R E N N U N G enebicyclo[2.2.1]hept-2-enes from the five-membered ring 2,6-enynols. The reactions are procedurally simple and high yielding, producing the aryl(halo)methylene-bridged bicycles in minutes under air and mild conditions.

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Facile Synthesis of Azaspirocycles via Iron Trichloride Promoted Cyclization/ Chlorination of Cyclic 8-Aryl-5-aza-5-tosyl-2-en-7-yn-1-ols. -Title compounds (I) and (III) undergo a very rapid transformation to the desired targets. The process is extended to the deaza analogues (V) with similar success. -(YEH*, M.-C. P.; FANG, C.-W.; LIN, H.-H.; Org. Lett. 14 (2012) 7, 1830-1833, http://dx.doi.org/10.1021/ol300434m ; Dep. Chem., Natl. Taiwan Norm. Univ., Taipei 116, Taiwan; Eng.) -Mais 31-095