制备 de dioxyde-2,2 de dioxathiolannes-1,3,2(I) a partir deglycols et 反应 脱硫酸盐 cycliques(I) avec divers 亲核试剂 (H - , N 3 - , F - , PhCO 2 - , NO 3 − , SCN − , PhCH 2 − )
Site-Selective Mono-Oxidation of 1,2-Bis(boronates)
作者:Lu Yan、James P. Morken
DOI:10.1021/acs.orglett.9b01204
日期:2019.5.17
Site-selective oxidation of vicinal bis(boronates) is accomplished through the use of trimethylamineN-oxide in 1-butanol solvent. The reaction occurs with good efficiency and selectivity across a range of substrates, providing 2-hydro-1-boronic esters which are shown to be versatile intermediates in the synthesis of chiral building blocks.
Methanesulfonamide: a Cosolvent and a General Acid Catalyst in Sharpless Asymmetric Dihydroxylations
作者:Mikko H. Junttila、Osmo O. E. Hormi
DOI:10.1021/jo8026998
日期:2009.4.17
effect on the reaction time and methanesulfonamide effect. The more polar the intermediate osmate ester, the faster is the reaction without methanesulfonamide and the smaller the accelerating methanesulfonamide effect. Methanesulfonamide had no accelerating effect in the asymmetric dihydroxylation of short chain terminal aliphatic olefins as a result of easier accessibility of terminal osmate ester
Osmium-catalyzed dihydroxylation of alkenes by H2O2 in room temperature ionic liquid co-catalyzed by VO(acac)2 or MeReO3
作者:Mikael Johansson、Auri A. Lindén、Jan-E. Bäckvall
DOI:10.1016/j.jorganchem.2005.04.033
日期:2005.8
immobilize a bimetallic catalytic system for H2O2-based dihydroxylation of alkenes. Osmium tetroxide was used as the substrate-selective catalyst with either VO(acac)2 or MeReO3 as co-catalyst. The latter serve as an electron transfer mediator (ETM) and activates H2O2. For an increased efficiency N-methylmorpholine is required as an additional ETM in most cases. A range of alkenes were dihydroxylated using
室温离子液体[bmim] PF 6用于固定双金属催化体系,用于烯烃的基于H 2 O 2的二羟基化。四氧化s用作底物选择催化剂,VO(acac)2或MeReO 3用作助催化剂。后者用作电子转移介体(ETM),并激活H 2 O 2。为了提高效率,在大多数情况下,需要N-甲基吗啉作为额外的ETM。使用这种坚固的双金属体系,一系列烯烃被二羟基化,结果表明,对于某些烯烃,催化体系可以循环使用多达五次。
The acid accelerated ruthenium-catalysed dihydroxylation. Scope and limitations
作者:Bernd Plietker、Meike Niggemann、Anja Pollrich
DOI:10.1039/b316546a
日期:——
Recently, we discovered a significant rate acceleration in RuO4-catalysed dihydroxylations of olefins by addition of Brönsted-acids resulting in a reduction of the catalyst loading to only 0.5 mol%. The present paper gives a full account on the optimisation protocol that led to the discovery of the beneficial influence of protic acids. A strong focus is set on the detailed description of the influence of different reaction parameters on both reactivity and selectivity. In the second part an intense investigation of scope and limitations will be presented. The results provided in this manuscript might lead to a deeper understanding of competing processes that influence the selectivity in RuO4-catalysed dihydroxylations.
Carbohydrate-Catalyzed Enantioselective Alkene Diboration: Enhanced Reactivity of 1,2-Bonded Diboron Complexes
作者:Lichao Fang、Lu Yan、Fredrik Haeffner、James P. Morken
DOI:10.1021/jacs.5b13174
日期:2016.3.2
Catalytic enantioselective diboration of alkenes is accomplished with readily available carbohydrate-derived catalysts. Mechanistic experiments suggest the intermediacy of 1,2-bonded diboronates.