Boron fluoride promoted cleavage of acetals by organocopper reagents application to asymmetric synthesis
作者:J.F. Normant、A. Alexakis、A. Ghribi、P. Mangeney
DOI:10.1016/0040-4020(89)80078-x
日期:1989.1
BF3. Et2O, organocopper and cuprate reagents promote the substitution of one alkoxy group of an acetal. Under the same conditions, alkoxy tetrahydropyrans react selectively, by ring cleavage. Chiral cyclic acetals, having a C2 axis of symmetry are diastereoselectively cleaved. The method serves to synthesize chiral secondary alcohols, after the removal of the chiral auxiliary.
Practical and Highly Selective CH Functionalization of Structurally Diverse Ethers
作者:Miao Wan、Zhilin Meng、Hongxiang Lou、Lei Liu
DOI:10.1002/anie.201407083
日期:2014.12.8
A trityl ion mediated CHfunctionalization of ethers with a wide range of nucleophiles at ambient temperature has been developed. The reaction displays high chemoselectivity and good functional group tolerance. The protocol also exhibits excellent regio‐ and diastereoselectivities for the unsymmetric ethers, thus stereoselectively generating highlyfunctionalized disubstituted 2,5‐trans tetrahydrofurans
Encapsulated perfume composition comprising at least one aminoplast core-shell microcapsule dispersed in a suspending medium, the microcapsule comprising a perfume-containing core encapsulated in a shell, said shell comprising a network of cross-linked aminoplast resin, wherein 75-100% of the resin comprises 50-90%, preferably from 60-85%, of a terpolymer and from 10-50%, preferably from 10-25%, of a polymeric stabilizer; the terpolymer comprising:
(a) from 20-35 wt %, preferably 22-30% by weight of moieties derived from at least one triamine,
(b) from 30-60 wt %, preferably 40-55% by weight of moieties derived from at least one diamine,
(c) from 20-35 wt %, preferably 22-30% by weight of moieties derived from the group consisting of alkylene and alkylenoxy moieties having 1 to 6 methylene units, preferably 1 to 4 methylene units and most preferably 1 methylene unit.
The encapsulated perfume composition is useful for the storage and dissemination of fragrance in various products, such as laundry products and fabric care products.
An encapsulated perfume composition comprising at least one perfume-containing aminoplast core-shell microcapsule dispersed in an aqueous suspending medium, the microcapsule being characterized in that it bears a positive charge.