A catalyticenantioselective Hosomi–Sakurai reaction of α-ketoesters has been developed. A copper(II) complex with a chiral bis(oxazoline) ligand bearing methanesulfonamide groups shows excellent catalytic activity to give α,α-disubstituted α-hydroxyesters in high yields with high enantioselectivities. This is the first successful method for the catalyticenantioselective 1,2-addition of α-ketoesters
Chiral allylating reagents, readily generated in situ from tin(II) catecholate [SnII(O2C6H4)], allyl halides, chiral dialkyl tartrates, and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), reacted smoothly with aldehydes or reactive ketones at −78 °C in the presence of a catalytic amount of copper salts to afford the corresponding optically active homoallyl alcohols. Allylation of aromatic aldehydes and pyruvates
手性烯丙基化试剂很容易从儿茶酚锡 (II) [SnII(O2C6H4)]、烯丙基卤化物、手性酒石酸二烷基酯和 1,8-二氮杂双环 [5.4.0] undec-7-烯 (DBU) 原位生成,反应平稳在催化量的铜盐存在下,在 -78 °C 下与醛或反应性酮反应,得到相应的光学活性高烯丙醇。本手性锡试剂对芳香醛和丙酮酸的烯丙基化反应以高产率 (81-99%) 和高对映选择性 (89-94%ee) 进行。此外,柠檬苹果酸二甲酯的两种对映异构体均由丙酮酸苄酯的烯丙基化产物制备。
Catalytic Use of Zinc Amide for Transmetalation with Allylboronates: General and Efficient Catalytic Allylation of Carbonyl Compounds, Imines, and Hydrazones
The efficient catalytic allylation of ketones, imines, and hydrazones with allylboronates using a catalytic amount of zinc amide is reported. In this reaction, the boron‐to‐zinc exchange process occurred smoothly to afford the corresponding allylzinc amides, and the desired allylation reactions proceeded in high efficiency (∼0.1 mol%). A mechanistic study revealed that transmetalation was a rate‐determining
METHODS AND INTERMEDIATES FOR THE PREPARATION OF OMACETAXINE AND CEPHALOTAXINE DERIVATIVES THEREOF
申请人:ALBANY MOLECULAR RESEARCH, INC.
公开号:US20180134724A1
公开(公告)日:2018-05-17
The present invention relates to methods and intermediates for the preparation of omacetaxine and cephalotaxine derivatives thereof. The resulting products are useful in the treatment of proliferative diseases and infectious diseases.