LaLi3tris(binaphthoxide) catalyst (LLB), which is prepared from LaCl3·7H2O (1 mol equiv), (R)- or (S)-BINOL dilithium salt (2.7 mol equiv), and NaO-t-Bu (0.3 mol equiv), is effective for the hydrophosphonylation of various aldehydes to give desired α-hydroxyphosphonates in up to 95% ee (88% yield). It is also noteworthy that with slow addition of the aldehydes the enantiomeric excesses of the products
The dimethyl phosphonate hydrophosphonylation of conjugated‐ and non‐conjugated aldehydes into their corresponding α‐hydroxy phosphonates was achieved using chiral aluminum–salalen complex 1 (see scheme).
Synthesis of an Optically Active Al(salalen) Complex and Its Application to Catalytic Hydrophosphonylation of Aldehydes and Aldimines
作者:Bunnai Saito、Hiromichi Egami、Tsutomu Katsuki
DOI:10.1021/ja0651005
日期:2007.2.1
serve as an efficient catalyst for hydrophosphonylation of aldehydes and aldimines, giving the corresponding alpha-hydroxy and alpha-amino phosphonates with high enantioselectivity, respectively. The scope of the hydrophosphonylation was wide, and both aliphatic and aromatic aldehydes and aldimines were successfully used as substrates for the reaction. The potent catalysis of the complex is attributed to
An aluminum binaphthyl Schiff base complex was found to be an efficient catalyst for enantioselective hydrophosphonylation of aldehydes. High enantioselectivities were obtained in reactions of both aromatic and aliphatic aldehydes (up to 84% and 86% ee, respectively).
Asymmetric hydrogenation of α-keto phosphonates with chiral phosphine–phosphoramidite ligands
作者:Qing Li、Chuan-Jin Hou、Yan-Jun Liu、Rui-Feng Yang、Xiang-Ping Hu
DOI:10.1016/j.tetasy.2015.05.007
日期:2015.7
Rh-catalyzed asymmetrichydrogenation of challenging α-ketophosphonates has been developed. With a new chiral phosphine–phosphoramidite ligand, a wide range of α-ketophosphonates were hydrogenated to afford the corresponding (R)-α-hydroxy phosphonates with moderate to good enantioselectivities (up to 87% ee).