Synthesis of Cyclic N-Tosyliminocarbonates by Lewis Acid Catalyzed Allylic Substitution of Trichloroacetimidates
作者:Liene Grigorjeva、Aigars Jirgensons
DOI:10.1002/ejoc.201200378
日期:2012.9
Allylic trichloroacetimidates bearing a δ-N-tosylcarbamoyloxy group were prepared in two steps from the corresponding diols, and their Bronsted and Lewisacidcatalyzed cyclization reactions were investigated. It was found that N-tosylcarbamates derived from secondary and tertiary alcohols bearing alkyl substituents undergo a chemoselective allylic alkylation to give N-tosyliminocarbonates in good
Stereoselective synthesis of substituted dienes by the double ortho ester Claisen rearrangement
作者:Suk-pyo Hong、Sung-jun Yoon、Byung-chan Yu
DOI:10.1016/j.tetlet.2004.12.015
日期:2005.1
This letter shows the highly stereoselective synthesis of substituted (E)-1,3-dienes from substituted propargylic diols via the double ortho ester Claisenrearrangement. The cyclohexyl-substituted diene undergoes thermal Diels–Alder cycloaddition with maleic anhydride to produce the corresponding bicyclic diester in highly stereoselective manner.
The substitution reactions of diphenyl sec‐alkyl phosphates with Ar2CH anions were swift and proceeded with inversion. In contrast, the diphenyl substituted‐cyclohexyl phosphates proceeded with inversion, but showed different reactivity depending on the relative stereochemistry of the substituent and the (PhO)2PO2 leaving group. The difference in reactivity was rationalized by computational calculation
磷酸二苯基仲烷基磷酸酯与Ar 2 CH阴离子的取代反应迅速进行,并进行了转化。相比之下,二苯基取代的环己基磷酸酯进行了转化,但根据取代基和(PhO)2 PO 2离开基团的相对立体化学,显示出不同的反应性。反应性的差异通过过渡能的计算得到合理化。
Lewis Acid Catalyzed Intramolecular Allylic Substitution of Bis(trichloroacetimidates): A Versatile Approach to Racemic Unsaturated Amino Acids
作者:Liene Grigorjeva、Aigars Jirgensons
DOI:10.1002/ejoc.201100060
日期:2011.5
Lewis acid catalyzed cyclization of trichloroacetimidates derived from 1,4-butenediols and 1,5-butenediols was achieved to give 4-vinyl oxazolines and 4-vinyloxazines in good to excellent yields. The cyclization products were transformed to protected unsaturated α- and β-amino acids, thus demonstrating the novel approach to access these important classes of compounds.
Synthesis and in vitro evaluation of ( R ), ( S ) and ( R / S )-2-hexyne-1,4-diol, a natural product produced by fungus Clitocybe catinus , and related analogs as potential anticancer agents
作者:Iza Mirela R.G. Princival、Jeiely G. Ferreira、Teresinha G. Silva、Jaciana S. Aguiar、Jefferson L. Princival
DOI:10.1016/j.bmcl.2016.04.060
日期:2016.6
for natural products and related analogs as potential anticancer agents has seen a significant growth worldwide. Since small sized propargylic diols can be found in nature and chemically synthesized, their evaluation against cancer cells has been of great interest, being a topic of relevance to be investigated. For this purpose, a scalable approach aiming at the synthesis of several propargylic diols