2,4,4,6-Tetrabromo-2,5-cyclohexadienone (TABCO), N-Bromosuccinimide (NBS) and Bromine as Efficient Catalysts for Dithioacetalization and Oxathioacetalization of Carbonyl Compounds and Transdithioacetalization Reactions
作者:Nasser Iranpoor、Habib Firouzabadi、Hamid Reza Shaterian、M. A. Zolfigol
DOI:10.1080/10426500211712
日期:2002.5.1
6-tetrabromo-2,5-cyclohexadienone (TABCO), N-bromosuccinimide (NBS), and bromine as efficient catalysts for conversion of carbonyl compounds to their cyclic and acyclic dithioacetals and 1,3-oxathiolanes under mild reaction conditions are described. These catalysts are also used for efficient transdithioacetalization of acetals, diacetals, ketals, acylals, enamines, hydrazones, and oximes with high
Stereoselective Synthesis of Nipecotic Acid Derivatives via Palladium-Catalyzed Decarboxylative Cyclization of γ-Methylidene-δ-valerolactones with Imines
作者:Ryo Shintani、Masataka Murakami、Tamio Hayashi
DOI:10.1021/ol802569q
日期:2009.1.15
A new synthetic method of multisubstituted nipecotic acid (piperidine-3-carboxylic acid) derivatives has been developed by way of palladium-catalyzeddecarboxylative cyclization of γ-methylidene-δ-valerolactones with imines. By employing the diethoxyphosphinoyl group as the N-protecting group for imines, the reaction proceeds smoothly with high diastereoselectivity. The products thus obtained can be
The nickel-catalyzed reductive coupling of alkynes and imines with Et(2)Zn as a reductant by using electron-rich phosphine ligands has been developed, affording various allylic amines with high yields and excellent chemoselectivities. Chiralinduction was also achieved in this reductive coupling reaction when a nickel catalyst containing a chiral spiro phosphine ligand was used.
A process for preparing formylphenylboronic acids of the formula (I) by reaction of protected chlorobenzaldehydes of the formula (II) with lithium in an inert solvent to form compounds of the formula (III) and subsequent reaction with a boron compound of the formula BY
3
to give compounds of the formula (I).
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