A regio‐ and enantioselective copper‐catalyzed 1,4‐conjugateaddition of trimethylaluminium to linear δ‐aryl‐substituted α,β,γ,δ‐unsaturated alkyl ketones was developed. A series of γ,δ‐unsaturated alkyl ketones were obtained in good yields with high regio‐ and enantioselectivity (up to 88% ee and 96:4 dr). Expansion of the reaction scope to substrates containing aromatic heterocycles also afforded
Construction of β to carbonyl stereogenic centres by asymmetric 1,4-addition of alkylzirconocenes to dienones and ynenones
作者:Zhenbo Gao、Stephen P. Fletcher
DOI:10.1039/c8cc01201f
日期:——
A new asymmetric addition of alkylzirconium species to dienones, a dienthioate, ynenones, and ynethionates with good yields and excellent ee's is reported.
Disclosed are substances which contain unsaturated, non-aromatic dialdehydes of formula (Ia) and/or the tautomer (Ib) thereof, wherein R
1
, R
2
, and R
3
are defined as indicated in claim
1
, along with at least one CH-acidic compound of formulas (II) and/or (III), wherein R
6
, R
7
, R
8
, R
9
, R
10
, Y, X
−
, Het, and X
1
are defined as indicated in claim
1
, in a cosmetic carrier. Said substances color keratinous fibers, especially human hair, in an intensive, colorfast, natural brown shade.
The invention relates to hair treatment products, comprising at least one copolymer made of 0.1 to 50% (in relation to the total number of monomers in the copolymer) monomers of the formula (I), wherein the unknowns are defined as in claim
1
, and A2) are monomers from the group of acrylic acid, methacrylic acid and the like, and—optionally non-ionic monomers from the group of acrylamide, vinyl alcohol, and the like, wherein the monomers A2 and A3 together represent 50 to 99.9% (in relation to the total number of monomers in the copolymer) of the copolymer, at least one silicon and at least one selected care product, wherein the products result in advantageous effects for skin and hair.
Palladium-Catalyzed Dienylations of Chelated Enolates
作者:Sankar Basak、Uli Kazmaier
DOI:10.1002/ejoc.200800519
日期:2008.8
Isomerization-free reactions of dienyl carbonates with chelated amino acid ester enolates at –78 °C provide important information concerning the mechanism of these dienylations. The formation of regioisomeric products can be explained by competing SN2/SN2′ reactions, and the product distribution can be influenced by the proper choice of the reaction conditions. Chiral allylic substrates show a significant