据报道,一种合成具有轻度可调节的宏观和介孔性的超轻氧化铁分层结构的简便方法。此方法需要在聚氨酯海绵的表面上生长多孔普鲁士蓝(PB)单晶,然后将PB晶体原位热转化为三维介孔氧化铁(3DMI)结构。与以前报道的超轻材料相比,3DMI架构具有分层的宏观和中孔框架,具有多种优势,包括高表面积(约117 m 2 g -1)和超低密度(6-11 mg cm -3))。此外,它们可以以千克规模合成。更重要的是,这些3DMI结构具有超顺磁性和可调节的亲水性/疏水性,因此可以实现有效的多相界面吸附和快速的多相催化。
An Oxidative [2,3]-Sigmatropic Rearrangement of Allylic Hydrazides
作者:Benjamin F. Strick、Devon A. Mundal、Regan J. Thomson
DOI:10.1021/ja2066219
日期:2011.9.14
The development of an efficient oxidative [2,3]-sigmatropicrearrangement of allylic hydrazides, via singlet N-nitrene intermediates, is reported. The requisite allylic hydrazide precursors are readily prepared and undergo smooth sigmatropic rearrangement upon exposure to iodosobenzene. The products of this novel transformation are shown to be useful precursors to a variety of compounds.
Veilchenriechstoffe. 60. Mitteilung. Synthese von ?-Jonon
作者:B. Willhalm、U. Steiner、H. Schinz
DOI:10.1002/hlca.19580410521
日期:——
Starting from 1,1-dimethyl-2-carbethoxy (or -carbomethoxy)-cyclohexan-3-one and passing through 1,1-dimethyl-2-hydroxymethyl-cyclohexan-3-one and 1,1,3-trimethyl-2-hydroxymethyl-cyclohexan-3-ol, a mixture of α- and γ-cyclogeraniol has been prepared.
Catalytic Asymmetric Spirocyclizing Diels–Alder Reactions of Enones: Stereoselective Total and Formal Syntheses of α-Chamigrene, β-Chamigrene, Laurencenone C, Colletoic Acid, and Omphalic Acid
作者:Santanu Ghosh、Johannes Eike Erchinger、Rajat Maji、Benjamin List
DOI:10.1021/jacs.2c01971
日期:2022.4.20
We disclose a general catalytic enantioselective Diels–Alderreaction of exo-enones with dienes to give spirocyclanes. The obtained products feature highly congested quaternary stereogenic spirocenters and are used in concise total and formal syntheses of several sesquiterpenes, including of α-chamigrene, β-chamigrene, laurencenone C, colletoic acid, and omphalic acid. The stereo- and regioselectivities
Aus 1,1-Dimethyl-2-oxymethyl-cyclohexanon-(3) wird das leicht dimerisierbare 1,1-Dimethyl-2-methylen-cyclohexanon-(3) in Verdünnung hergestellt und mit Acetessigester nach Michael kondensiert, wobei je nach Versuchsbedingungen ein mono- oder ein bicyclisches Kondensationsprodukt entstcht. Beide ergeben bei der Säure-spaltung 1,1-Dimethyl-2-(β-carboxy-äthyl)-3-oxy-3-carboxy-methylcyclohexan. Diese Oxy-dicarbonsäure
cycloaddition, ring reorganization through Criegee oxidative cleavage and programmed aldol condensations, conformationally controlled hydrogenation, and Pd-catalyzed carboxylation. The absolute configuration of omphalic acid was defined for the first time via the asymmetric total synthesis facilitated by a derivatization resolution protocol.