Novel Method of Tetramic Acid Synthesis: Silver-Catalyzed Carbon Dioxide Incorporation into Propargylic Amine and Intramolecular Rearrangement
作者:Tomonobu Ishida、Ryo Kobayashi、Tohru Yamada
DOI:10.1021/ol500806u
日期:2014.5.2
starting materials and harsh heating conditions in basic media. The present report provides a conceptually new synthetic strategy for the synthesis of tetramic acid derivatives from easily available propargylicamines and carbon dioxide with a silver salt and DBU under mild reaction conditions.
Ag NPs decorated on a COF in the presence of DBU as an efficient catalytic system for the synthesis of tetramic acids <i>via</i> CO<sub>2</sub> fixation into propargylic amines at atmospheric pressure
作者:Swarbhanu Ghosh、Rostam Ali Molla、Utpal Kayal、Asim Bhaumik、Sk. Manirul Islam
DOI:10.1039/c9dt00017h
日期:——
tetramic acids from a variety of propargylic amine derivatives at 60 °C under atmospheric pressure of carbondioxide via formation of oxazolidinones, where CO2 acts as a C1 reagent. The Ag@TpPa-1 catalyst exhibited excellent recycling efficiency for the synthesis of tetramic acid with no leaching of Ag from the catalyst surface.
to substituted 3‐keto pyridines or 4‐picolines in very good yields. This pathway is in contrast to their known cyclization in the presence of Au(I) or Au(III) catalysts which provides 1,4‐oxazepines, instead. The enaminones are formed in situ upon mixing a conjugated allenone or allenyl ester with the alkynylamine, thus the pyridine‐forming transformation is typically a onepot process.
TiO 2上的可回收负载型Au纳米颗粒催化N-炔丙基或N-同炔丙基β-烯胺酮的环化,然后进行脱氢(芳构化),从而以非常好的收率产生取代的3-酮吡啶或4-甲基吡啶。该途径与已知在Au(I)或Au(III)催化剂存在下环化的相反,后者提供1,4-氧杂氮杂pine。烯胺酮是在将共轭的Allenone或Allenyl酯与炔基胺混合后原位形成的,因此形成吡啶的转化通常是一锅法。
Direct Asymmetric α‐C−H Addition of N‐unprotected Propargylic Amines to Trifluoromethyl Ketones by Carbonyl Catalysis
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。