Yuanzhu Gai

Exo selective diels-alder reactions mediated by Et2AlCl in the presence of H2O

Abstract Diels-Alder reactions of 4-triisopropylsilyloxy-2H-thiopyran with N-(2-propenoyl)-2-oxazolidones are promoted by Lewis acids. Unusually high exo selectivity is observed when Et2AlCl in the presence of H2O is used as the Lewis acid. The involvement of the sulfur atom with the bidentate Lewis acid dichlorodiethyl-μ-oxodialuminum is postulated.

Simple Methods for the Preparation of Enantiomerically Pure Abscisic Acid (ABA) Analogues from (S)-(+)-ABA

Abstract (1′S, 2Z, 4E)-3-Methyl-5-(1-hydroxy-2,6,6-trimethyl-4-oxo-2-cyclohexenyl)-2,4-pentadienoic acid (abscisic acid, ABA) is efficiently converted into the corresponding aldehyde, primary alcohol, and triol derivatives using readily available reagents (oxalyl chloride, NaBH4, MnO2) and simple reaction conditions.

Synthesis of (-)-bactobolin from D-glucose and from (+)-actinobolin.

Abstract The preparation of (-)- 16 from (+)- 3 constitutes a formal enantiospecific synthesis of (-)-bactobolin from D-glucose. The key transformation involves the diastereoselective addition of LiCHCl 2 to 7 in the presence of CeCl 3 . The synthesis of (+)- 3 from (+)-actinobolin sulfate is reported and illustrates the conversion of (+)-actinobolin into (-)-bactobolin.