2-diazo-N-phenylacetamide 、 对氟苯甲醛 在
zirconium complex of (R)-3,3'-diiodo-BINOL on 3 Å MS 作用下,
以
乙腈 为溶剂,
以96%的产率得到3-(4-fluorophenyl)-N-phenyloxirane-2-carboxamide
Hydroxytetraphenylenes as Chiral Ligands: Application to Asymmetric Darzens Reaction of Diazoacetamide with Aldehydes
作者:Henry Wong、Guo-Li Chai、Jian-Wei Han
DOI:10.1055/s-0036-1588880
日期:——
with rigid conformations are potential candidates for employment as chiral ligands in asymmetric synthesis. Highly diastereo- and enantioselective Darzens reactions between aldehydes and diazo-N,N-dimethylacetamide were found to be catalyzed by a chiral titanium complex formed in situ from Ti(O i Pr)4 and chiral 1,16-dihydroxytetraphenylene, leading to the formation of cis-glycidic amides in moderate
献给教授迪特尔·恩德斯博士在他的70之际个生日。 抽象的 具有刚性构象的羟基四亚苯基是在不对称合成中用作手性配体的潜在候选者。发现醛与重氮-N,N-二甲基乙酰胺之间的高度非对映选择性和对映选择性Darzens反应是由由Ti(O i Pr)4和手性1,16-二羟基四亚苯基原位形成的手性钛络合物催化的,从而导致形成中等至高收率的顺式-缩水甘油酰胺,具有出色的对映体纯度(40–99%收率,高达99%ee)。 具有刚性构象的羟基四亚苯基是在不对称合成中用作手性配体的潜在候选者。发现醛与重氮-N,N-二甲基乙酰胺之间的高度非对映选择性和对映选择性Darzens反应是由由Ti(O i Pr)4和手性1,16-二羟基四亚苯基原位形成的手性钛络合物催化的,从而导致形成中等至高收率的顺式-缩水甘油酰胺,具有出色的对映体纯度(40–99%收率,高达99%ee)。
Storable and Air-Stable Zirconium Complex-Catalyzed Highly Enantioselective Darzens Reaction of Diazoacetamide with Aldehydes
作者:Long He、Wei-Jun Liu、Lei Ren、Tao Lei、Liu-Zhu Gong
DOI:10.1002/adsc.200900845
日期:——
An asymmetric Darzensreaction of aldehydes with diazo‐N,N‐dimethylacetamide (3) catalyzd by an air‐stable and storable chiral zirconium Lewis acid catalyst, which is formed from 3,3′‐diiodobinaphthol and tetrabutoxyzirconium, gives solely the cis‐glycidic amides in high yields with excellent enantioselectivity (up to 97% yield, >99% ee).