Ram S. Mohan

An efficient method for the chemoselective synthesis of acylals from aromatic aldehydes using bismuth triflate

Aromatic aldehydes are smoothly converted into the corresponding acylals in good yields in the presence of 0.10 mol% Bi(OTf)3·xH2O. Ketones are not affected under the reaction conditions. The highly catalytic nature of bismuth triflate and the fact that it is relatively non-toxic, easy to handle and insensitive to small amounts of air and moisture makes this procedure especially attractive for large-scale synthesis.

A Facile and Efficient Method for the Rearrangement of Aryl-substituted Epoxides to Aldehydes and Ketones using Bismuth Triflate

Abstract Aryl-substituted epoxides undergo smooth rearrangement in the presence of 0.01–0.1 mol% Bi(OTf) 3 · x H 2 O. The rearrangement is regioselective with aryl-substituted epoxides, and products arise from cleavage of the benzylic CO bond. The highly catalytic nature of this method coupled with the fact that the reagent is relatively non-toxic, easy to handle and inexpensive make it an attractive alternative to more corrosive and toxic Lewis acids, such as BF 3 ·Et 2 O, currently used to effect epoxide rearrangements.

Bismuth(III) Oxide Perchlorate Promoted Rearrangement of Epoxides to Aldehydes and Ketones

Abstract Aryl-substituted epoxides and aliphatic epoxides with a tertiary epoxide carbon undergo smooth rearrangement in the presence of 10–50 mol% bismuth(III) oxide perchlorate, BiOClO 4 ·×H 2 O, to give carbonyl compounds. The rearrangement is regioselective with aryl substituted epoxides and a single carbonyl compound arising from cleavage of benzylic C–O bond is formed. BiOClO 4 ·×H 2 O is relatively non-toxic, insensitive to air and inexpensive, making this catalyst an attractive alternative to more corrosive and toxic Lewis acids such as BF 3 ·Et 2 O or InCl 3 currently used to effect epoxide rearrangements.

Oxidation of Benzoins to Benzils using Bismuth(III) Nitrate-Copper(II) Acetate

Benzoins are oxidized to benzils in excellent yields by 0.4 equivalents of Bi(NO3)3·5H2O and 4 mol% of Cu(OAc)2. Bi(NO3)3·5H2O is a stable, inexpensive, commercially available solid. The relatively low cost and low toxicity of bismuth(III) nitrate makes this procedure a particularly attractive method for oxidation of benzoins.

Bismuth Triflate Catalyzed Allylation of Acetals: A Simple and Mild Method for Synthesis of Homoallyl Ethers

Abstract The allylation of acetals using allyltrimethylsilane is efficiently catalyzed by bismuth triflate (1.0 mol%). The reaction proceeds smoothly at room temperature to afford the corresponding homoallyl ether in good yield. The mild reaction conditions, the low toxicity of bismuth salts, and the high catalytic efficiency of the system make this procedure particularly attractive for large-scale synthesis.

Bismuth (III) Acetate: A New Catalyst for Preparation of Azlactones via the Erlenmeyer Synthesis

Abstract Bismuth(III) acetate catalyzes the synthesis of azlactones from aromatic aldehydes in moderate to good yields via the Erlenmeyer synthesis. The relatively low toxicity and low cost of bismuth(III) acetate make this procedure particularly attractive.

Environmentally Friendly Organic Synthesis Using Bismuth Compounds. Bismuth Trifluoromethanesulfonate-Catalyzed Allylation of Dioxolanes

A bismuth trifluoromethanesulfonate (triflate)-catalyzed (2.0 mol-%) multicomponent reaction involving the allylation of dioxolanes followed by in situ derivatization with anhydrides to generate highly functionalized esters has been developed under solvent-free conditions. Most reagents used to date for allylation of dioxolanes are highly corrosive and are often required in stoichiometric amounts. In contrast, the use of a relatively non-toxic and non-corrosive bismuth(iii)-based catalyst makes this methodology especially attractive for scale-up.

Platform technology for dienone and phenol–formaldehyde architectures

Claisen–Schmidt condensations, yielding only water as a by-product, performed on building blocks serving as shape-selective male or female terminals and unions, enable the preparation of diverse molecular structures including novel linear rods and semi-elliptical, rectangular or trapezoidal macrocycles. Isoaromatization affords a corresponding range of phenol-formaldehyde derivatives, in atom economical reactions.

Bismuth(III) Triflate Catalyzed Allylation of Cyclic Acetals and Dithianes Followed by in situ Derivatization to Generate Highly Functionalized Esters

The allylation of acyclic acetals to generate homoallyl ethers has been well documented in the literature. Several catalysts have been developed for this purpose including TiCl4, AlCl3, BF3·Et2O,3 tritylperchlorate,4 montmorillonite,5 TMSN(SO2F)2, ISiMe3, TMSOTf,8 TiCp2(CF3SO3)2, tris(p-bromophenyl)aminium hexachloroantimonate,10 triarylpyrilium salts,11 TMSNTf2, BiBr3, Sc(OTf)3, Bi(OTf)3, and CuBr.17 In contrast, there are far fewer reports in the literature of the corresponding allylation of cyclic acetals. The allylation of a number of 1,3-dioxolanes and 1,3-dioxanes catalyzed by TMSOTf has been reported by Hunter and co-workers18 (Scheme 1).

Erratum to “A mild and chemoselective method for the deprotection of tert-butyldimethylsilyl (TBDMS) ethers using iron(III) tosylate as a catalyst” [Tetrahedron Lett. 51 (2010) 1056–1058]

Erratum Erratum to ‘‘A mild and chemoselective method for the deprotection of tert-butyldimethylsilyl (TBDMS) ethers using iron(III) tosylate as a catalyst” [Tetrahedron Lett. 51 (2010) 1056–1058] Jason M. Bothwell, Veronica V. Angeles, James P. Carolan, Margaret E. Olson, Ram S. Mohan * Laboratory for Environmentally Friendly Organic Synthesis, Department of Chemistry, Bloomington, IL 61701, United States