Trichloroisocyanuric Acid, as an Industrial Chemical, Promotes Transthioacetalization of Diacetals of 2,2-Bis (Hydroxymethyl)-1,3-propanediol and Cleavage of Thioacetals
Trichloroisocyanuric acid has been used as a mild, efficient, and new catalyst for transthioacetalization of diacetals of 2,2-bis (hydroxymethyl)-1,3-propanediol in CH 2 Cl 2 at room temperature. A clean, easy, and general method for efficientdeprotection of thioacetals to their corresponding carbonyl compounds using trichloroisocyanuric acid/silica gel and water system also is described.
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
A highly enantioselective asymmetric Darzens reaction catalysed by proline based efficient organocatalysts for the synthesis of di- and tri-substituted epoxides
A new class of easily available and readily tunable proline based chiral organocatalysts was found to efficiently catalyse an unprecedented highly enantioselective asymmetric Darzens reaction of α-chloro ketones and substituted α-chloro ketones with various aldehydes, which directly produces optically active di- and tri-substituted chiral epoxides with higher product yields (up to 97 %) and excellent
2,4,4,6-Tetrabromo-2,5-cyclohexadienone (TABCO) as a Versatile, Efficient, and Chemoselective Catalyst for the Acetalization and Transacetalization of Carbonyl Compounds, the Preparation of Acetonides from Epoxides and Acylals (1,1-Diacetates) from Aldehydes
The efficient and chemoselective preparation of acetals and ketals from carbonyl compounds, transacetalization reactions, the conversion of epoxides to acetonides, and the preparation of acylals from aldehydes in the presence of catalytic amounts of 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TABCO) are described.
different α-branched aldehydes were treated with various malonate derivatives to give enantiomerically enriched Knoevenagel products with higher chemical yield (up to 97%) and excellent e.r up to 99.68 0.32 via dynamic kinetic resolution. Further the Knoevenagel adduct was converted into enantiomerically enriched valuable γ-alkyl-substituted amides without loss in enantiomeric ratio.