58672-91-6Relevant articles and documents
PHOTOLABILE PRO-FRAGRANCES
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Paragraph 0119-0126, (2015/04/15)
Many fragrances that provide a scent of freshness tend to be highly volatile and are therefore not very economical when used in typical applications such as washing or cleaning processes, so they have to be used in relatively large quantities to be able to produce adequate effects. The disclosed photolabile pro-fragrances provide a much longer-lasting sense of fragrance, in particular with a scent of freshness, when used in typical applications, thus allowing said fragrances to be used efficiently.
Michael addition of stannyl ketone enolate to α,β-unsaturated esters catalyzed by tetrabutylammonium bromide and an ab initio theoretical study of the reaction course
Yasuda, Makoto,Chiba, Kouji,Ohigashi, Noriyuki,Katoh, Yasuhiro,Baba, Akio
, p. 7291 - 7300 (2007/10/03)
Michael addition of stannyl ketone enolates to α,β-unsaturated esters was accomplished in the presence of a catalytic amount of tetrabutylammonium bromide (Bu4NBr). Other typical systems using lithium enolate or silyl enolate with catalysts (TiCl4 or Bu4NF) failed to give the desired products. The bromide anion from Bu4NBr coordinates to the tin center in enolate to accelerate the conjugate addition where a five-coordinated tin species was generated. The coordination of the bromide anion significantly raises the HOMO level of tin enolate and enhances its nucleophilicity. The conjugate addition provides the intermediate Michael adduct, which has an ester enolate moiety, and the adduct immediately transforms to α-stannyl γ-ketoester by keto - enol tautomerization. This step contributes to the stabilization of the product system and leads to a thermodynamically favorable reaction course. An ab initio calculation reveals that the activation energy in the reaction using the bromide anion is lower than that of the reaction without using it. The transition state in either reaction course has a linear structure, not a cyclic one. This system can be applied to a variety of tin enolates and α,β-unsaturated carbonyls involving enoates, enones, and unsaturated amides.
The Michael-type Reaction of B-Iodo-9-BBN/Ethoxyethyne Adduct to α,β-Unsaturated Ketones. A Selective Synthesis of δ-Keto Esters
Kawamura, Fumitoshi,Tayano, Takao,Satoh, Yoshitaka,Hara, Shoji,Suzuki, Akira
, p. 1723 - 1726 (2007/10/02)
The adduct formed from B-iodo-9-borabicyclononane and ethoxyethyne reacts with α,β-unsaturated ketones under mild conditions to give δ-keto esters in excellent yield selectively.
