Electron Impact Induced Loss of C-5/C-8 Substituents of 1,2,3,4-Tetrahydroisoquinolines, V: Synthesis and Mass Spectrometric Fragmentation of Dihydroisoindole Derivatives
摘要:
AbstractC‐8‐substituted N‐methyl‐1,2,3,4‐tetrahydroisoquinoline radical cations lose the complete substituent in a one step reaction giving rise to an unexpected ion at m/z 146, which is probably identical with the dihydroisoindolyl‐methyl‐cation A. The dihydroisoindoles 1, 10, and 16 were prepared as potentially alternative precursors of ion A. However, the ion at m/z 146 in their El mass spectra is of very low intensity, so CID‐experiments for structural comparison could not be performed. The electron impact induced fragmentations of 1, 10, and 16 are discussed.
A Convenient and Versatile Method for the Preparation of α-Hydroxymethyl Ketone Derivatives from the Corresponding Allyl Silyl Ethers or Allyl Carboxylates
作者:Yung-Son Hon、Ying-Chieh Wong、Kuo-Jui Wu
DOI:10.1002/jccs.200800134
日期:2008.8
The ozonolysis of 1-substituted allyl silyl ethers or 1-substituted allyl carboxylates followed by treatment with bases gave the corresponding α-silyloxymethyl- or a-acyloxymethyl-ketones in good yields. It is proposed to proceed via the corresponding α-silyloxy- or α-acyloxyaldehydes intermediates followed by 1,4-group migration. The results of theoretical calculations are applicable to explain the
Alkene migration to the end-terminal carbon bearing a phenyl group over a chiral siloxy carbon center in Heck reaction
作者:Akiko Ida、Naoyuki Hoshiya、Jun'ichi Uenishi
DOI:10.1016/j.tet.2015.03.018
日期:2015.9
The Heck reaction of aryl bromide with a terminal alkene substrate having a chiral center at the allylic position and a phenyl substituent at another terminal carbon is reported. An alkene migration to the phenyl-substituted end carbon is observed, along with the typical Heck reaction. This zipper-type migration occurs through multiple internal carbon bonds, and the stereochemistry of the internal
Diastereoselective C−H Bond Amination for Disubstituted Pyrrolidines
作者:Diana A. Iovan、Matthew J. T. Wilding、Yunjung Baek、Elisabeth T. Hennessy、Theodore A. Betley
DOI:10.1002/anie.201708519
日期:2017.12.4
diastereoselective synthesis of 2,5‐disubstituted pyrrolidines from aliphatic azides. Experimental and theoretical studies of the C−H amination reaction mediated by the iron dipyrrinato complex (AdL)FeCl(OEt2) provided a model for diastereoinduction and allowed for systematic variation of the catalyst to enhance selectivity. Among the ironalkoxide and aryloxide catalysts evaluated, the iron phenoxide complex
我们在此报告了从脂肪族叠氮化物非对映选择性合成 2,5-二取代吡咯烷的改进方法。由二吡啶铁配合物 ( Ad L)FeCl(OEt 2 ) 介导的 C−H 胺化反应的实验和理论研究提供了非对映诱导模型,并允许对催化剂进行系统变化以提高选择性。在评估的铁醇盐和芳氧化物催化剂中,苯酚铁络合物在生成具有高非对映选择性的顺式2,5-二取代吡咯烷方面表现出优异的性能。
Unified, Radical-Based Approach for the Synthesis of Spiroketals
作者:Michiel de Greef、Samir Z. Zard
DOI:10.1021/ol070488+
日期:2007.4.1
S-(3-chloro-2-oxo-propyl)-O-ethyl xanthate 1 by two consecutive xanthate transfer reactions, followed by spirocyclization of the resulting dihydroxy ketones, provides a flexible and highly convergent access to diversely substituted spiroketals, containing five-, six-, and seven-membered rings.
Rhodium-Catalyzed Regio- and Enantioselective Addition of <i>N</i>-Hydroxyphthalimide to Allenes: A Strategy To Synthesize Chiral Allylic Alcohols
作者:Zi Liu、Bernhard Breit
DOI:10.1021/acs.orglett.7b03709
日期:2018.1.5
We achieved the first Rh-catalyzed regio- and enantioselectiveadditions of N-hydroxyphthalimide to allenes. This transformation is accomplished via mild reaction conditions, leveraging on Josiphos SL-J003-2 as a chiral ligand to furnish branched O-allyl compounds in good yields with moderate to excellent enantioselectivities. The substrate scope is broad, and various functional groups are tolerated