In order to find non-narcotic analgesics, 54 compounds of amino-tert-alcohol, in which a variety of substituent groups were involved at the carbon atom in 1-position and at the amino group, were synthesized by reacting various α-and β-amino acid esters with Grignard reagents. These amino acid esters were readily reacted with alkyl Grignard reagents to give the expected compounds. However, when bulky aromatic Grignard reagents were submitted to react, the reactions were found to stop at the stage of intermediate formation of the corresponding ketones.
interesting and important to perform a nitrogen or oxygen selective reaction with interesting substrates. These atom specific reactions are crucial to specifically synthesis of specific compounds. An enantioselective N‐specific reaction of nitrosobenzene with unmodified aldehydes was successfully achieved catalyzed first by a variety of primaryamine‐based organocatalysts with higher yield and enantioselectivity
Synthesis of new C2-symmetric bis(β-hydroxy amide) ligands and their applications in the enantioselective addition of alkynylzinc to aldehydes
作者:Xin-Ping Hui、Chao Yin、Zhi-Ce Chen、Lu-Ning Huang、Peng-Fei Xu、Gui-Fang Fan
DOI:10.1016/j.tet.2008.01.036
日期:2008.3
chiral C2-symmetric bis(β-hydroxy amide) ligands was synthesized via the reaction of isophthaloyl dichloride and aminoalcohols derived from l-amino acid. The titanium(IV) complex of C2-symmetric chiral ligand 3b was effective for the asymmetric alkynylation of aldehydes and the propargyl alcohols were obtained in high yields (up to 94%) and high enantiomeric excesses (up to 98%) under optimized conditions
The first catalytic asymmetric addition of diethylzinc to aldehyde promoted by chiral thiourea
作者:Zhi Guo Qiao、Tian Hua Shen、Zhen Fang Fu、Jun Qi Li、Hong Wang、Qing Bao Song
DOI:10.1016/j.cclet.2011.07.015
日期:2011.11
Abstract A series of C2 -symmetric and asymmetricchiral thiourea derivatives were synthesized from commercial l -phenylalanine. All of the new compounds have been fully characterized by IR, 1 H NMR, 13 C NMR, MS spectra and elemental analyses. The chiral thioureas were used as chiralligands in the catalytic enantioselective ethylation of aldehydes with diethylzinc, the corresponding sec-alcohols
摘要从商品化的1-苯丙氨酸合成了一系列C 2对称和不对称的手性硫脲衍生物。所有新化合物均已通过IR,1 H NMR,13 C NMR,MS光谱和元素分析进行了全面表征。在条件优化后,手性硫脲被用作醛与二乙基锌催化醛的对映选择性乙基化的手性配体,获得了相应的仲醇,具有优异的对映选择性(最高87.1%ee)和高收率(最高76.7%)。
Enantioselective alkynylation of aromatic aldehydes catalyzed by new chiral oxazolidine ligands
Newchiral oxazolidines were conveniently synthesized from natural amino acids in three simple steps with good yields. The use of chiral oxazolidine ligands for the enantioselective alkynylation of aldehydes provides a simple, practical and inexpensive method to generate chiral propargyl alcohols with 85–99% ee.