41174-45-2

Upstream product

• 954-16-5 2,4,6-Trimethylbenzophenon 
• 98-88-4 benzoyl chloride 
• 108-67-8 1,3,5-trimethyl-benzene 
• 97799-60-5 α-mesityl-α-phenylacetyl chloride 
• 3901-04-0 α-mesityl-α-phenylacetic acid 
• 77787-77-0 α-mesityl-α-phenyl-2,4,6-trimethylacetophenone 

Relevant academic research and scientific papers

TRANSITION METAL-PROMOTED REACTIONS. VII. NOVEL REACTIONS OF ACID CHLORIDES WITH PENTACARBONYLIRON IN AROMATIC SOLVENTS

Upon treatment with Fe(CO)5 in an aromatic hydrocarbon solvent aromatic acid chlorides gave a mixture of triarylmethane and tetraarylethane.The reaction may proceed via benzaldehyde and diarylmethanol intermediates.A free radical mechanism is proposed.

Diverse photochemistry of sterically congested α-arylacetophenones: ground-state conformational control of reactivity

The effects of α and ortho substituents on the photoreactivity of various α-(o-tolyl)- and α-mesitylacetophenones have been measured. In general, both types of substitution lower the efficiency of cyclization to 2-indanol derivatives in solution. 1,3-Rearrangement of an α-mesityl group to group to form enol ethers and α-cleavage to radicals compete to various degrees, in some cases becoming dominant. Quenching studies in solution show that all three reactions occur from the same n,π* triplet state; α-substitution lowers rate constants for δ-hydrogen abstraction and increases those for α-cleavage and 1,3-rearrangement. X-ray crystal analysis and MMX calculations both show that any additional substitution at the α-carbon of α-aryl (phenyl, tolyl, or mesityl) ketones favors conformers in which the α-aryl group have rotated 120° away from eclipsing the carbonyl. In agreement with this, α-phenyl and α-(o-tolyl) ketones undergo γ-hydrogen abstraction (Norrish type II reaction) with rate constants almost as large as those of the nonarylated ketones. NMR line-broadening studies show that, in most of the α-mesityl ketones, the rate constants for rotation around the mesityl-α-carbon bond (104-106 s-1) are much slower than triplet decay. The same is true for rotations around the carbonyl-α-carbon bond in the α-arylisobutyrophenones. Considered of the spectroscopic evidence, triplet lifetimes, and calculated rotational barriers indicates that ground-state conformational preferences determine which excited-state reactions can occur in most of these ketones. Many of the ketones that cyclize in low yield in solution do so in much higher yield when irradiated as solids, presumably because α-cleavage to radicals becomes mostly revertible. The solid-state reactivity demonstrates that hydrogen abstraction can occur from what are supposedly nonideal geometries; in particular, large values (60-70°) for the dihedral angle and rate constants for hydrogen abstraction in solution plane of the carbonyl π system. The relationship between this angle and rate constants for hydrogen abstraction in solution is discussed. Rate constants for α-cleavage reveal the separate influences of steric congestion and conjugation of the developing benzyl radicals. The 1,3-aryl migration to oxygen appears to arise from initial CT complexation of the α-aryl to the carbonyl; subsequent bonding of oxygen to the benzene ring apparently relieves steric congestion. The 50:50 initial mixture of Z and E enol ethers suggests that the rearrangement is adiabatic, generating enol ether in its twisted triplet state. A large enhancement of indanol yields by alcoholic solvents is suggested to involve protonation of the same CT complex.

Conformational control of photoreactivity: Three α-mesityl ketones that undergo efficient radical cleavage

α-Mesitylisobutyropohenone, 1,2-dimesitylethanone, and 2-phenyl-1,2-dimesitylethanone all undergo only one photoreaction in solution, α-cleavage to acyl radicals. Quantum yields are all over 0.30 and triplet rate constants are ≥5 x 108 s-1. In each case, bond rotations are so slow that reaction occurs from the preferred ground state geometries, which hold the molecules in conformations ideal for cleavage. The large cleavage rate constants reflect relief of steric strin as well as ideal orientation of π and σ orbitals.

Reductive Coupling of Aromatic Ketones by Low-valent Titanium Salts

Reaction of sterically congested aromatic ketones with the McMurry reagent (4TiCl3, LiAlH4) in tetrahydrofuran yields is not only the olefins (E- and Z-isomers), but also the corresponding ethanes and some other products.We have studied the minor or non-normal products of this reaction.