Mass Efficiency of Alkene Syntheses with Tri- and Tetrasubstituted Double Bonds

Abstract

Environmental factors and process mass intensity were determined and evaluated for more than 30 standard procedures for the synthesis of alkenes with tri- and tetrasubstituted double bonds. They contain some of the most commonly used reaction types for the synthesis of alkenes, e.g., Peterson, Shapiro, Heck, Suzuki, and Negishi. Four kinds of syntheses of geminal dihalides were also considered. The highest efficiency is found when employing the olefin metathesis reaction followed by other modern catalytic processes, and the lowest efficiency is found with the Julia–Lythgoe process. Several types of McMurry coupling reactions show that the efficiency is dependent on the variant of this type of reaction. These metrics point out weaknesses as well as optimization potentials and show which performances can be expected. This could provide an orientation when mass efficiency aspects are relevant during the synthesis planning of alkenes with tri- and tetrasubstituted double bonds.

Regio- and stereoselective synthesis of tetra- and triarylethenes by N-methylimidodiacetyl boron-directed palladium-catalysed three-component coupling

“…A lkenes represent one of the most important classes of organic compounds. Although numerous methods exist for alkene preparation, the synthesis of polysubstituted alkenes in a regio-and stereochemically defined manner still poses a significant challenge to synthetic organic chemists [1][2][3][4] . In principle, six isomers exist for fully substituted alkenes with four different R groups.…”

“…Nevertheless, given the typically small electronic and steric differences between the individual aryl groups (compared to the difference between aryl and alkyl groups), the selective synthesis of tetraarylethenes bearing four different aromatic substituents is inherently challenging. While the classical double bond-forming methods such as olefin metathesis 8 , Wittig 9 and McMurry 10 reactions are effective for tetraarylethene synthesis, the stereoselectivity of these protocols is typically a problem [1][2][3][4] . Platform synthesis is a powerful strategy to realize the synthesis of complex molecules in a programable and diversity-oriented format.…”

“…As such, the identification of proper reaction conditions to enable orthogonal reactivities is necessary but represents a challenge. Guided by the above-mentioned concept, we reasoned the sp 3 -hybridized MIDA (N-methyliminodiacetyl) boron might be an optimal choice [29][30][31][32] . Early studies reveal the notable stability of MIDA boron towards diverse reaction conditions.…”

Selective Synthesis of Tetrasubstituted Olefins by Copper‐Mediated Acetoxythiolation of Internal Alkynes: Scope and Mechanistic Studies

“…In the case of 3ae,asimilar analysis was performed by using the = CMe group and the ortho protons of the Bn group (seet he Supporting Information). The reaction also toleratedt he presence of substituents in the phenyl ring (see substrates 1a-e), and good yields of 3ba-ea were obtained if alkyl groups (Me, 1b and 1c; tBu, 1d)o rs trong electron-withdrawing groups (CF 3 , 1e)w ere tested.H owever,t he use of strong electron-donating groups, such as OMe, gave only small conversions (< 5%)o wing to extensive decomposition.…”

“…The synthesis of tetrasubstituted olefins with completec ontrol of the regio-and stereoselectivities is still ac hallenge for synthetic chemists, as highlighted in recentr eviews. [1][2][3][4][5][6][7] New synthetic methods are continuouslyb eing screened, and intense research devotedt oa chieving more performant pathways while keeping simple methodologies is ongoing. [8][9][10][11][12][13][14][15][16][17][18] The interest in these particular substrates resides in their versatility as startingm aterials and in their pharmacological, photochemical, and electrochemical properties.…”