acid-catalyzed asymmetricBaylis-Hillmanreaction is described. Good to high enantioselectivities were obtained using 3 mol % chiral catalyst. Novel camphor-derived dimerized ligands were prepared from the condensation of (+)-ketopinic acid with the corresponding diamines and hydrazine under acidic conditions. When alpha-naphthyl acrylate was used as a Michael acceptor, the reaction is complete within
Chiral chelating agents and chiral catalysts, which are formed from the chiral chelating agents and metal, are described. One chiral chelating agent has a general formula (1) as illustrated below:
1
wherein R represents H, methyl, ethyl, a primary, secondary or tertiary straight, branched or cyclic alkyl group having 3-7 carbon atoms, a heterocyclic or aromatic group, an aromatic group substituted at the 2-, 3- or 4-position, an aromatic-like group, or a naphthyl or naphthyl-derived group, and n is an integer between 0 and 4.
Design and synthesis of bistereogenic chiral ionic liquids and their use as solvents for asymmetric Baylis–Hillman reactions
作者:Satish Garre、Erica Parker、Bukuo Ni、Allan D. Headley
DOI:10.1039/b808502a
日期:——
containing two chiral centers in the side chain bonded to the 2-position of the imidazolium cation and different anions have been synthesized, characterized and used as chiral solvents for asymmetricBaylis-Hillman (BH) reactions; good yields and fair enantioselectivities were obtained.
The organocatalytic asymmetric allylic etherification reaction of Morita–Baylis–Hillmancarbonates and silanols was reported for the first time. With modified cinchonaalkaloid (DHQD)2PYR as the catalyst, a series of aromatic, heterocyclic, or aliphatic Morita–Baylis–Hillmancarbonates (25 examples) worked well with triphenylsilanol, affording the corresponding products in moderate to good yields (up