atom efficient ‘trifluoroacetic ester/ketone metathesis’ has been sincerely witnessed. Enolizable alkyl (at least two non-hydrogen atoms) aryl ketones were found to react readily with ethyl trifluoroacetate under the promotion of NaH to afford trifluoroacetic ester/ketone exchange products, trifluoromethyl ketones (TFMKs), and aromatic acid esters, which were quite different from the general Claisen
Synthesis of Trifluoromethyl Ketones via Tandem Claisen Condensation and Retro-Claisen C–C Bond-Cleavage Reaction
作者:Dongmei Yang、Yuhan Zhou、Na Xue、Jingping Qu
DOI:10.1021/jo400280p
日期:2013.4.19
builds on the use of a tandem process involving Claisen condensation and retro-Claisen C–C bond cleavage reaction. Enolizable alkyl phenyl ketones were found to react readily with ethyl trifuoroacetate under the promotion of NaH to afford trifluoroacetic ester/ketone exchange products, trifluoromethyl ketones, which were quite different from the general Claisen condensation products, β-diketones. This
Despite the very low acidity of the inert α C−H bonds (pKa≈42.6), directasymmetric α-C(sp3)−H addition of N-unprotected propargylic amines to trifluoromethyl ketones has been achieved by using a chiral pyridoxal as the carbonyl catalyst, producing a broad variety of chiral alkynyl β-aminoalcohols in high yields with excellent stereoselectivities (up to 84 % yield, >20 : 1 dr, 99 % ee).
尽管惰性 α C−H 键的酸度非常低 (p K a ≈ 42.6),但通过使用手性吡哆醛,已经实现了 N-未保护的炔丙胺与三氟甲基酮的直接不对称 α-C( sp 3 )−H 加成作为羰基催化剂,以高产率和出色的立体选择性(高达 84% 产率,>20:1 dr,99% ee)生产多种手性炔基 β-氨基醇。
Asymmetric Biomimetic Transamination of Trifluoromethyl Ketones
In the presence of chiral pyridoxamine 4b as the catalyst and 2,2-diphenylglycine (3) as the amine source, asymmetric biomimetic transamination of trifluoromethyl ketones produces optically active α-trifluoromethyl amines 6 in 81–98% yields with 88–95% ee’s under mild conditions.
Red emission organic phosphor with broad excitation band
申请人:Zhang Xiao
公开号:US20050194885A1
公开(公告)日:2005-09-08
A phosphor of the general formula Eu(A)
3−x
(B)
2x+2
where A is a β-diketone and B is an organic phosphine oxide (R
3
PO—R═, aryl, alkylene acyl, phenyl and their derivatives. The phosphor being synthesize in a single step process where a lanthanide ion solution is added to a β-diketone and organic phosphine oxide mixture. The phosphor having a high intensity red line emission at between 610 to 620 nm depending on ligand groups.