Role of the Heteroatoms in the Complex Metal Hydride Reduction of 2-<i>t</i>-Butyl-1,3-dioxan-5-one and 3-Oxoquinolizidine: Comparison of Their Reactivity and Stereochemistry with Those of the Corresponding Carbocyclic Compounds
作者:Yasuhisa Senda、Hiroshi Sakurai、Hiroki Itoh
DOI:10.1246/bcsj.72.285
日期:1999.2
The complexmetalhydridereductions of 2-t-butyl-1,3-dioxan-5-one (1) and 3-oxoquinolizidine (3) are faster than those of the corresponding carbocyclic compounds, 4-t-butylcyclohexanone (2) and trans-2-decalone (4). The stereoselectivities were similar in the LiAlH4 reduction, but the heteracyclohexanones exhibited higher stereoselectivity with NaBH4. These facts are discussed in terms of the intramolecular
The enantioselective Horner-Wadsworth-Emmons reaction of 2-fluoro-2-dietliylphosphonoacetates with sigma-symmetric prochiral 2-substituted-1,3-dioxan-5-ones and 4-substituted-cyclohexanones was investigated by employing Sn(OSO2CF3)(2) and N-ethylpiperidine in the presence of an external chiral ligand, (S)-(-)-1-methyl-2-(1-piperidinomethyl)pyrrolidine. A chiral alpha-fluoro-alpha,beta-unsaturated ester was obtained in up to 80% ce. (C) 2002 Elsevier Science Ltd. All rights reserved.