New chiraldiphosphinites were prepared starting from (+)-diethyl tartrate. The asymmetrichydrogenation of dehydroamino acids, itaconic acid and dehydrodipeptides was studied using Rh(I)-diphosphinite catalysts. In the hydrogenation of dehydroamino acid derivatives, an introducion of ω-(dimethylamino)alkyl group in the ligands did not raise the optical yield. By the use of Rh(I)-diphosphinite having
Asymmetric Catalytic Enantio- and Diastereoselective Boron Conjugate Addition Reactions of α-Functionalized α,β-Unsaturated Carbonyl Substrates
作者:Jian-Bo Xie、Siqi Lin、Shuo Qiao、Guigen Li
DOI:10.1021/acs.orglett.6b01998
日期:2016.8.5
established for the asymmetric boron conjugate addition of B2pin2 onto α-functionalized (involving C, N, O, and Cl) α,β-unsaturated carbonyls under mild, neutral conditions involving Cu[(S)-(R)-ppfa]Cl, AgNTf2, and alcohols. The dual additives of AgNTf2 and alcohols were found to play crucial roles for achieving high catalytic activity and enantio- and diastereoselectivity (up to 98% ee and 70:1 dr).
Asymmetric Reduction of Aromatic α-Dehydroamino Acid Esters with Water as Hydrogen Source
作者:Yuze Dai、Jingchao Chen、Zheting Wang、Ting Wang、Lin Wang、Yong Yang、Xingfang Qiao、Baomin Fan
DOI:10.1021/acs.joc.1c00426
日期:2021.5.21
The asymmetric reduction of aromatic α-dehydroamino acid esters with water as the hydrogensource was developed by a Rh/Cu co-catalytic system. The reaction tolerates various functional groups, providing a valuable synthetic tool to access chiral α-amino acid esters readily. Moreover, the present methodology also was applied in the cost-effective and easy to handle preparation of chiral deuterated
A highly efficient Rh-catalyzed hydrogenation of functionalized olefins has been realized by a new family of highly rigid chiral ferrocenylphosphine-spiro phosphonamidite ligands. Excellent enantiocontrol (>99% ee in most cases) was achieved with a wide range of α-dehydroamino acid esters and α-enamides. This practicable catalytic system was further applied in the scalable synthesis of highly optically
通过一个新的高刚性手性二茂铁基膦-螺亚膦酰胺配体家族,实现了功能化烯烃的高效 Rh 催化氢化。使用范围广泛的 α-脱氢氨基酸酯和 α-烯酰胺可以实现出色的对映控制(大多数情况下 >99% ee )。该实用催化体系进一步应用于西那卡塞和d-苯丙氨酸的高光学纯关键中间体的可扩展合成。