[(Trimethylsilyl)methyl]copper(I) species: versatile reagents to prepare functionally substituted allylic silanes

Abstract

Smooth Sn2' reactions in -alkynyl and -allenyl oxiranes, in esters derived from -allenic alcohols, and in the bis(methanesulfonate) derived from 1,4-dihydroxy-2-butyne were observed with the reagent [ (trimethylsilyl)methyl]copper(I). In this way, several allylic silanes bearing functional groups became available. Another route to functionally substituted allylic silanes was elaborated by adding [(trimethylsilyl)methyl]copper(I) or its homocuprate derivative to alkynes such as 2-alkynoic esters, ethoxyacetylene, 1-alkynyl sulfides, and 1-alkynyl sulfones. The addition reactions appeared to occur regiospecifically and in many cases also with high stereoselectivity. A 1,4-bis[ (trimethylsilyl)methyl]-substituted butatriene derivative could be obtained by sequential addition of the bis[(trimethylsilyl)methyl]cuprate compound and methyl iodide to a 1-alkynyl sulfide. For one case it was shown that the addition of [ (trimethylsilyl)methyl] copper(I) to 1-alkynyl sulfones can be used to prepare sulfur-free 1-alkenes bearing in the ¡5-position the (trimethylsilyl)methyl group.Organocopper(I) species are versatile reagents for organic synthesis.1 They may be used as nucleophiles in substi-

Second Generation, Orally Active, Antimalarial, Artemisinin-Derived Trioxane Dimers with High Stability, Efficacy, and Anticancer Activity

“…Scheme illustrates our two-step synthesis of trioxane dimer conjugated diene 4 in overall 63% yield from artemisinin ( 1 ) via formation of two new carbon−carbon bonds, using the linker 2,3-bis(trimethylsilylmethyl)-1,3-butadiene. , Our original design of this diene dimer 4 was based on its anticipated ease of preparation; an analogous successful double coupling of an allylic bis-silane with dihydroartemisinin acetate ( 3 ) proceeds smoothly . Diene dimer 4 was expected to be desirable due to the well-known propensity of 1,3-dienes to enter easily into Diels−Alder cycloadditions , leading to rigid six-membered carbocycles.…”

A 4+3 Cycloaddition Approach to the Synthesis of (±)-Sterpurene

“…This was then photolyzed in methanol to give the β-ketoester 3 in a 76% yield via a Wolff rearrangement . Treatment with triethylamine and triflic anhydride yielded the vinyl triflate, which was then coupled with trimethylsilylmethyl cuprate and reduced to afford the alcohol 4 in 73% overall yield. The alcohol 4 was then treated with acidic silica gel to provide the diene 5 in 75% yield via a vinylogous Peterson olefination …”

Dimeric Copper and Lithium Thiolates: Comparison of Copper Thiolates with Their Lithium Congeners

“…35 For the synthesis of Cu(I) thiolates, various routes have used reagents that have proved to be useful copper sources, for instance, [Cu(CH 3 CN) 4 ]PF 6 has been used to synthesize copper(I) thiolato and selenolato complexes, 28 Cu(I) halides 51 and CuBr(SMe 2 ) 52 have proved to be useful copper reagents in producing three-coordinate copper thiolato polymers and trinuclear copper thiolato species, and mesitylcopper(I) has been used to produce copper aryloxides 53 and copper amides. 54 Initially, we investigated the treatment of a Cu(I) alkyl {CuCH 2 SiMe 3 } 4 55 with the terphenyl thiol HSAr iPr4 with the elimination of volatile SiMe 4 to synthesize dimeric Cu(I) thiolates (Figure 2); however, this reaction resulted in considerable decomposition of the copper alkyl to produce copper metal.…”

“…Initially, we investigated the treatment of a Cu­(I) alkyl {CuCH 2 SiMe 3 } 4 with the terphenyl thiol HSAr iPr4 with the elimination of volatile SiMe 4 to synthesize dimeric Cu­(I) thiolates (Figure ); however, this reaction resulted in considerable decomposition of the copper alkyl to produce copper metal.…”