A Green Approach for Allylations of Aldehydes and Ketones: Combining Allylborate, Mechanochemistry and Lanthanide Catalyst

Secondary and tertiary alcohols synthesized via allylation of aldehydes and ketones are important compounds in bioactive natural products and industry, including pharmaceuticals. Development of a mechanochemical method using potassium allyltrifluoroborate salt and water, to successfully perform the allylation of aromatic and aliphatic carbonyl compounds is reported for the first time. By controlling the grinding parameters, the methodology can be selective, namely, very efficient for aldehydes and ineffective for ketones, but by employing lanthanide catalysts, the reactions with ketones can become practically quantitative. The catalyzed reactions can also be performed under mild aqueous stirring conditions. Considering the allylation agent and its by-products, aqueous media, energy efficiency and use of catalyst, the methodology meets most of the green chemistry principles.

Synthesis and characterization of Bi(iii) immobilized on triazine dendrimer-stabilized magnetic nanoparticles: a reusable catalyst for the synthesis of aminonaphthoquinones and bis-aminonaphthoquinones

A novel method for synthesis of aminonaphthoquinone derivatives using Fe₃O₄@TDSN–Bi(iii) is reported.

A Ce(OTf)3/PyBox catalyzed enantioselective Hosomi–Sakurai reaction of aldehydes with allyltrimethylsilane

An approach to the efficient synthesis of enantioselective homoallylic alcohols has been developed by the use of a catalytic amount of a cerium/PyBox complex.

Bismuth-catalyzed addition of silyl nucleophiles to carbonyl compounds and imines

Bismuth triflate was found to be an efficient catalyst both in the Mannich-type reaction of silyl enolates and in the Sakurai reaction of allyltrimethylsilane with N-alkoxycarbonylamino sulfones. The reactions proceeded smoothly with a low catalyst loading of Bi(OTf)(3)·4H(2)O (0.5-5.0 mol%) to afford the corresponding protected β-amino carbonyl compounds and homoallylic amines in very good yields (up to 96%). The latter compounds could also be obtained via a bismuth-mediated three-component reaction. We have also developed an efficient vinylogous Mukaiyama aldol reaction of 2-(trimethylsilyloxy)furan with various aromatic aldehydes mediated by bismuth triflate in a low catalyst loading (1 mol%). The reaction proceeds rapidly and affords the corresponding 5-[hydroxy(aryl)methyl]furan-2(5H)-ones in high yields with good to very good diastereoselectivities (diastereoisomeric ratios>98:2). Such selectivities, although previously reported with other Lewis acids, could be achieved with a much lower catalyst loading. 5-[Hydroxy(alkyl)methyl]furan-2(5H)-ones derived from ketones could also be obtained with good diastereoselectivities. The vinylogous Mukaiyama aldol reaction has also been extended to 2,2-dimethyl-6-methylene-4-(trimethyl-silyloxy)-1,3-diox-4-ene using 1 mol% of Bi(OTf)(3)·4H(2)O.

Applications of bismuth(III) compounds in organic synthesis

This review article summarizes the applications of bismuth(III) compounds in organic synthesis since 2002. Although there are an increasing number of reports on applications of bismuth(III) salts in polymerization reactions, and their importance is acknowledged, they are not included in this review. This review is largely organized by the reaction type although some reactions can clearly be placed in multiple sections. While every effort has been made to include all relevant reports in this field, any omission is inadvertent and we apologize in advance for the same (358 references).