An eco-friendly synthesis of cycliccarbonates through a Lewisacidcatalyzed cyclization of tert-butyl carbonates is described. These cycliccarbonates are precursors of 1,2- and 1,3-diols, and the developed method was applied to a short synthesis of a diarylheptanoid, (3S,5S)-alpinikatin.
COPPER (I)-CATALYZED REACTION OF ISOPRENE BROMOHYDRIN WITH ORGANOLITHIUM REAGENT
作者:Shuki Araki、Yasuo Butsugan
DOI:10.1246/cl.1980.185
日期:1980.2.5
The reaction of isoprene bromohydrin (1-bromo-2-methyl-3-buten-2-ol) (1) with ethyl-, propyl- and butyllithium in the presence of copper (I) iodide leads to the exclusive formation of the vinyl group migrated 2-alkyl-4-penten-2-ols (3d–3f), in contrast to the reaction with methyl-, phenyl- and benzyllithium, which yields the corresponding 2-methyl-4-substituted-2-buten-l-ols (2a–2c).
Facile preparation of allylzinc species from allylboronates and zinc amide via a boron-to-zinc exchange process and their reactions with carbonyl compounds, imines and hydrazones
作者:Yi Cui、Yasuhiro Yamashita、Shū Kobayashi
DOI:10.1039/c2cc34340a
日期:——
Facile formation of allylzinc species from allylboronate and zinc amide was discovered. The boron-to-zinc exchange process occurred smoothly to afford the corresponding allylzinc amides, which were successfully employed in catalytic allylation reactions with electrophiles. Asymmetric catalysis using a chiral zinc amide is also reported.
Catalytic Use of Zinc Amide for Transmetalation with Allylboronates: General and Efficient Catalytic Allylation of Carbonyl Compounds, Imines, and Hydrazones
The efficient catalytic allylation of ketones, imines, and hydrazones with allylboronates using a catalytic amount of zinc amide is reported. In this reaction, the boron‐to‐zinc exchange process occurred smoothly to afford the corresponding allylzinc amides, and the desired allylation reactions proceeded in high efficiency (∼0.1 mol%). A mechanistic study revealed that transmetalation was a rate‐determining
A simple and efficient hydrolyzing method for tetrahydropyranyl ethers
作者:Adam Shih-Yuan Lee、Feng-Yih Su、Yuan-Cheng Liao
DOI:10.1016/s0040-4039(98)02602-1
日期:1999.2
A series of tetrahydropyranylethers are hydrolyzed to the corresponding alcohols in a CBr4/CH3OH (5% / 5mL) reaction system under refluxing. This method also enables to deprotect other functionalities such as acetals and ketals.