16958-34-2

Upstream product

• 14799-82-7 (cyclopropylmethyl)triphenylphosphonium bromide 
• 100-52-7 benzaldehyde 
• 16958-35-3 (E)-1-cyclopropyl-2-phenyl ehtylene 
• 114507-05-0 triphenylphosphonium perchlorate 
• 1449-46-3 benzyltriphenylphosphonium bromide 
• 1489-69-6 Cyclopropanecarboxaldehyde 
• 21777-85-5 cyclopropylphenylethyne 
• 4747-15-3 1-(2-methoxyvinyl)benzene 
• 23719-80-4 cyclopropylmagnesium bromide 

Downstream Products

• 37689-22-8 3-phenylcyclopentene 
• 16958-35-3 (E)-1-cyclopropyl-2-phenyl ehtylene 

Relevant academic research and scientific papers

Using alcohols as simple H2-equivalents for copper-catalysed transfer semihydrogenations of alkynes

Copper(i)/N-heterocyclic carbene complexes enable a transfer semihydrogenation of alkynes employing simple and readily available alcohols such as isopropanol. The practical overall protocol circumvents the use of commonly employed high pressure equipment when using dihydrogen (H2) on the one hand, and avoids the generation of stoichiometric silicon-based waste on the other hand, when hydrosilanes are used as terminal reductants.

Are perpendicular alkene triplets just 1,2-biradicals? Studies with the cyclopropylcarbinyl clock

Thermochemical studies of perpendicular alkene triplets demonstrate that their energies are almost exactly those expected from Benson estimations using group equivalents for appropriate free radicals as models for the termini (the two essential carbons of the alkene triplet). If these species are to be described as 1,2-biradicals, their reactivities in reactions for which the termini act independently should be similar to corresponding reactivities for appropriate free-radical models. We have used the "cyclopropylcarbinyl clock", the rearrangement of a cyclopropylcarbinyl radical to the corresponding homoallyl radical, to test such a model. We have synthesized cis- and trans-β-cyclopropylstyrene (cis-1 and trans-1), α-cyclopropylstyrene (2), α-cyclopropylindene (3), and β-cyclopropylindene (4). We have studied their triplet chemistry and have examined the transients produced upon triplet sensitization by nanosecond laser flash photolysis. The results are consistent with two basic hypotheses: (1) that, when able to access the perpendicular configuration, cyclopropylcarbinyl ring opening occurs at the rate expected from an appropriate monoradical model and (2) that, when constrained in a higher energy (near-planar) geometry, the rate of ring opening is accelerated.

Dinuclear cobalt complex-catalyzed stereodivergent semireduction of alkynes: Switchable selectivities controlled by H2O

Catalytic semireduction of internal alkynes to alkenes is very important for organic synthesis. Although great success has been achieved in this area, switchable Z/E stereoselectivity based on a single catalyst for the semireduction of internal alkynes is a longstanding challenge due to the multichemo- and stereoselectivity, especially based on less-expensive earth-abundant metals. Herein, we describe a switchable semireduction of alkynes to (Z)- or (E)-alkenes catalyzed by a dinuclear cobalt complex supported by a macrocyclic bis pyridyl diimine (PDI) ligand. It was found that cis-reduction of the alkyne occurs first and the Z-E alkene stereoisomerization process is formally controlled by the amount of H2O, since the concentration of H2O may influence the catalytic activity of the catalyst for isomerization. Therefore, this protocol provides a facile way to switch to either the (Z)- or (E)-olefin isomer in a single transformation by adjusting the amount of water.

Stereoselective Chromium-Catalyzed Semi-Hydrogenation of Alkynes

Chromium complexes have found very little applications as hydrogenation catalysts. Here, we report a Cr-catalyzed semi-hydrogenation of internal alkynes to the corresponding Z-alkenes with good stereocontrol (up to 99/1 for dialkyl alkynes). The catalyst comprises the commercial reagents chromium(III) acetylacetonate, Cr(acac)3, and diisobutylaluminium hydride, DIBAL?H, in THF. The semi-hydrogenation operates at mild conditions (1-5 bar H2, 30 °C).

Harnessing Applied Potential: Selective β-Hydrocarboxylation of Substituted Olefins

The construction of carboxylic acid compounds in a selective fashion from low value materials such as alkenes remains a long-standing challenge to synthetic chemists. In particular, β-addition to styrenes is underdeveloped. Herein we report a new electrosynthetic approach to the selective hydrocarboxylation of alkenes that overcomes the limitations of current transition metal and photochemical approaches. The reported method allows unprecedented direct access to carboxylic acids derived from β,β-trisubstituted alkenes, in a highly regioselective manner.

Stereoselective Alkyne Hydrogenation by using a Simple Iron Catalyst

The stereoselective hydrogenation of alkynes constitutes one of the key approaches for the construction of stereodefined alkenes. The majority of conventional methods utilize noble and toxic metal catalysts. This study concerns a simple catalyst comprised of the commercial chemicals iron(II) acetylacetonate and diisobutylaluminum hydride, which enables the Z-selective semihydrogenation of alkynes under near ambient conditions (1–3 bar H2, 30 °C, 5 mol % [Fe]). Neither an elaborate catalyst preparation nor addition of ligands is required. Mechanistic studies (kinetic poisoning, X-ray absorption spectroscopy, TEM) strongly indicate the operation of small iron clusters and particle catalysts.

Nickel-Catalyzed system for the cross-coupling of alkenyl methyl ethers with grignard reagents under mild conditions

A nickel-catalyzed cross-coupling of alkenyl methyl ethers with Grignard reagents, under mild conditions, is described. These conditions allowed access to various stilbenes and heterocyclic stilbenic derivatives as well as to a potential anticancer agent DMU-212.

Palladium porphyrin catalyzed hydrogenation of alkynes: Stereoselective synthesis of cis -alkenes

(Tetraphenylporphyrin)palladium was developed as a catalyst for the chemoselective and stereoselective hydrogenation of alkynes to cis-alkenes by the syn-addition of hydrogen. Alkynes containing various functional groups were tolerated in the reaction, which gave the corresponding cis-alkenes in good to excellent yields. Georg Thieme Verlag Stuttgart New York.

Cycloreversion of β-lactams via photoinduced electron transfer

The radical anions of β-lactams, photogenerated in the presence of DABCO as an electron donor, undergo cycloreversion via N-C4 bond cleavage, back electron transfer and final C2-C3 bond cleavage, leading to olefins. The involved intermediates are 1,4-radi