关键词： Ethers   Hydrocarbons   Vinyl   Stereochemistry   Organic reactions  

摘要： Rhodium(II) octanoate catalyzed decomposition of 2-diazo-3-siloxybutenoates, containing (R)-pantolactone as a chiral auxiliary, in the presence of vinyl ethers results in the diastereoselective synthesis of cyclopropanes with high asymmetric induction. Treatment of the cyclopropanes with tetrabutylammonium fluoride results in desilylation and ring expansion of the resulting acylcyclopropanes to 2,3-dihydrofurans with retention of stereochemistry.

关键词： Peptides and proteins   Reaction products   Cyclization   Organic compounds   Olefin metathesis  

摘要： An efficient and versatile method has been developed for the synthesis of a selectively protected 2,7-diaminosuberic acid derivative. A Grubbs ring-closure olefin metathesis reaction was used as a key step on an allylglycine-derived template.

关键词： 氨基酸   不对称合成   热力学   构型熵  

摘要： 从热力学角度分析了氨基酸不对称化学合成中光学收率与构型熵及温度的关系

关键词： 手性有机硼   制备   不对称合成  

摘要： 本文综述高纯度手性烃基硼烷及其衍生物的制备方法,以及它们在不对称合成中的重要应用。

关键词： 二氢异恶唑   鹰爪素碱   衍生物   不对称合成  

摘要： 将光学纯的鹰爪素碱用于氧化亚氮乙酸乙酯的制备，在丙烯酸乙酯的存在下，得到光学活性的３，５－二羧酸乙酯－４，５－二氢异唑，其主要对映体的绝对构型为Ｓ。

关键词： ferrocene   asymmetric synthesis   nucleophilic 1,2-addition   hydrazones   cleavage reactions  

摘要： The aldehydes 1 and 5 were converted to the corresponding SAMP hydrazones 2 and 6, respectively. Subsequent nucleophilic 1,2-addition of organolithium reagents to the C-N double bonds and cleavage of the N-N hydrazine bond using an excess of *** afforded (1-ferrocenylalkyl)amines (N-protection --> 4) and 1,1'-bis(1-aminoalkyl)ferrocenes (N-protection --> 8) in good overall yields (32-88%), with very high enantiomeric excesses (ee = 90-98%) and dl/meso ratios of up to 95:5.

关键词： Peptides and proteins   Reaction products   Nitrogen compounds   Monomers   Enantioselective synthesis  

摘要： The sulfinimine asymmetric Strecker synthesis, the addition of ethyl aluminum cyano alkoxide, "EtAl(OR)CN", to sulfinimine 10, has been applied to a concise highly efficient four-step enantioselective synthesis of (R)-(4-methoxy-3,5-dihydroxyphenyl)glycine (3) and its derivatives in >97% ee. These epimerization-sensitive arylglycines are precursors of the key central amino acid of vancomycin and related glycopeptide antibiotics.

关键词： Carboxylic acids  

摘要： The X-ray structure analysis of the title compound, C22H27NO3, establishes unambiguously the relative and absolute configurations of the two asymmetric C atoms, C5 (S) and C6 (S), based on the known R absolute configuration of the C10 atom, and provides essential information on the transition state of the Michael reaction leading to its formation.

关键词： Amides   Anions   Hydrolysis   Mixtures   Molecular structure  

关键词： 铱(I)配合物   Schiff碱   不对称氢转移反应   铜(Ⅱ)配合物