Synthesis of Carbocyclic Hydantocidins via Regioselective and Diastereoselective Phosphine-Catalyzed [3 + 2]-Cycloadditions to 5-Methylenehydantoins
作者:Tien Q. Pham、Stephen G. Pyne、Brian W. Skelton、Allan H. White
DOI:10.1021/jo050827h
日期:2005.8.1
The phosphine-catalyzed [3 + 2]-cycloaddition of 5-methylenehydantoins 4 with the ylides 5, derived from addition of tributylphosphine to the 2-butynoic acid derivatives, 6a−d, gives spiro-heterocyclic products. The camphor sultam derivative 6b gives optically active products. Noteable was that the ylides derived from ethyl 2-butynoate and the 3-(2-butynoyl)-1,3-oxazolidin-2-one derivatives 6c and
A noncatalyzed conjugate addition reaction of alkylaluminium compounds to 1,3-dibenzyl-5-methylene-2,4-imidazolidinedione 1 led to the exclusive formation of single and double conjugate adducts (2 and 3, respectively). The ratio of 2 : 3 depended on the reaction temperature and the concentration of 1.
Application of a New Chiral Phosphepine to the Catalytic Asymmetric Synthesis of Highly Functionalized Cyclopentenes That Bear an Array of Heteroatom-Substituted Quaternary Stereocenters
作者:Yuji Fujiwara、Gregory C. Fu
DOI:10.1021/ja2049012
日期:2011.8.10
the design and synthesis of a new chiral phosphepine, the first catalytic asymmetric method for the [3 + 2] cycloaddition of allenes with olefins has been developed that generates cyclopentenes that bear nitrogen-, phosphorus-, oxygen-, and sulfur-substituted quaternary stereocenters. A wide array of racemic γ-substitutedallenes can be employed in this stereoconvergent process, which occurs with good
A Convenient Synthesis of 1,3-Dibenzyl-5-methylenehydantoin
作者:T. Ravindranathan、S. V. Hiremath、Kalpana Gosavi、D. Rajagopal Reddy
DOI:10.1055/s-1989-27140
日期:——
An efficient and simple two-step synthesis of 1,3-dibenzyl-5-methylenehydantoin from cystine is described.
本研究描述了一种从胱氨酸高效、简单地分两步合成 1,3-二苄基-5-亚甲基海因的方法。
Density Functional Theory Guided Design of Exo-Selective Dehydroalanine Dienophiles for Application Toward the Synthesis of Palau'amine
作者:Timothy A. Cernak、James L. Gleason
DOI:10.1021/jo701866g
日期:2008.1.1
Diels−Aldercycloadditions of dehydroalanine derivatives with cyclopentadiene, applicable to the synthesis of palau'amine, were investigated experimentally and using DFT computations at the B3LYP/6-31G* level of theory. Oxazolone and thiohydantoin dienophiles were found to be significantly more reactive than hydantoins or dehydroalanine methyl esters. The increased reactivity of the thiohydantoins