Conjugate addition of potassiumtrifluoro(organo)borates 2 to dehydroalanine derivatives 1, mediated by a chiral rhodium catalyst and in situ enantioselective protonation, afforded straightforward access to a variety of protected alpha-amino esters 3 with high yields and enantiomeric excesses up to 95%. Among the tested chiral ligands and proton sources, Binap, in combination with guaiacol (2-methoxyphenol)
Nickel‐Catalyzed Asymmetric Hydrogenation of 2‐Amidoacrylates
作者:Yawen Hu、Jianzhong Chen、Bowen Li、Zhenfeng Zhang、Ilya D. Gridnev、Wanbin Zhang
DOI:10.1002/anie.201916534
日期:2020.3.23
chiral bisphosphine ligand, was found to be an efficientcatalyst for the asymmetric hydrogenation of 2-amidoacrylates, affording the chiral α-aminoacid esters in quantitative yields and excellent enantioselectivity (up to 96 % ee). The active catalyst component was studied by NMR and HRMS, which helped us to realize high catalytic efficiency on a gram scale with a low catalyst loading (S/C=2000).
发现富含地球的镍与合适的手性双膦配体配合使用,是2-酰胺基丙烯酸酯不对称氢化的有效催化剂,以定量收率和优异的对映选择性(高达96%ee)提供了手性α-氨基酸酯。通过NMR和HRMS对活性催化剂组分进行了研究,这有助于我们以克级实现高催化效率且催化剂负载量低(S / C = 2000)。氢化产物可以简单地转化为手性α-氨基酸,β-氨基醇及其生物活性衍生物。此外,使用氘标记实验和计算计算研究了催化机理。
Nickel-Catalyzed Asymmetric Transfer Hydrogenation of Olefins for the Synthesis of α- and β-Amino Acids
作者:Peng Yang、Haiyan Xu、Jianrong Steve Zhou
DOI:10.1002/anie.201407744
日期:2014.11.3
The field of asymmetric (transfer) hydrogenation of prochiral olefins has been dominated by noble metal catalysts based on rhodium, ruthenium, and iridium. Herein we report that a simple nickel catalyst is highly active in the transfer hydrogenation using formic acid. Chiral α‐ and β‐amino acid derivatives were obtained in good to excellent enantioselectivity. The key toward success was the use of
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
Chemoenzymatic synthesis of a novel ligand for rhodium-catalysed asymmetric hydrogenation
作者:Brian Adger、Ulrich Berens、Matthew J. Griffiths、Michael J.K elly、Ray McCague、John A. Miller、Christopher F. Palmer、Stanley M. Roberts、Rüdiger Selke、Ute Vitinius、Guy Ward
DOI:10.1039/a704136e
日期:——
The hydrogenation of alkenes 7a–g using a chiral rhodium catalyst
6 (based on a bicyclo[3.2.0]heptane framework) takes place to give the
phenylalanine derivatives 8a–g with remarkably high
stereoselectivity (59–92% ee).