Highly enantioselective synthesis of (+)- and (−)-perfluoroalkyl(aryl) homoallyl alcohols
摘要:
Asymmetric allylboration of perfluoroaldehydes and fluorine substituted aromatic aldehydes with (d)Ipc(2)BAll and 2-Icr(2)BAll has been investigated. Both enantiomers of the fluorinated homoallyl alcohols were obtained in high yields and excellent enantiopurity (95-99% eel. (C) 2001 Elsevier Science Ltd. All rights reserved.
Two new chiral diphenylphosphine dioxides bearing an original bis(triazolyl) backbone were prepared through a two‐step sequence. The key reactioninvolves a copper‐catalyzed [3+2] cycloaddition/dimerization reaction leading to the formation of five bonds in one chemical step with 100 % atom efficiency. Interestingly, these ligands exhibited good to excellent catalytic activities as chiral Lewis base
of C10-BridgePHOS oxides possessing different substituted groups on the diphenyl phosphine system were synthesized and tested as organocatalysts in the allylation of aldehydes with allyltrichlorosilane, providing chiral homoallylic alcohols. These types of organocatalysts showed high catalytic activity and only 2 mol% catalyst loading was required to induce short reaction times. Under optimal reaction
Axially chiral
<i>N,N′‐</i>
dioxides ethers for catalysis in enantioselective allylation of aldehydes
作者:Shijie Wu、Yongfei Xing、Jie Wang、Xingchen Guo、Huajie Zhu、Wan Li
DOI:10.1002/chir.23122
日期:2019.11
A series of axially chiral ethers synthesized from biscarboline N,N′‐dioxides, (S)‐1a to (S)‐1n, was investigated in enantioselectivity addition reactions of allyltrichlorosilane with a series of substituted aldehydes, including bulky substituted aldehydes. High enantioselectivities (up to 96%ee) were achieved using the catalyst (S)‐1k at 1 mol % loading.
A chiral oxazoline for catalytic enantioselective Nozaki-Hiyama-Kishi allylation and vinylation of aldehydes
作者:Sharad V. Kumbhar、Chinpiao Chen
DOI:10.1016/j.catcom.2020.106166
日期:2021.1
Asymmetric allylation and vinylation of aldehydes with allyl halides and vinyl halides have been achieved using the chromium(II)-oxazoline catalyst. The catalyst promotes the highly efficient enantioselective Nozaki–Hiyama-Kishi (NHK) allylation of aldehydes usingallyl bromide, producing the corresponding homoallylic alcohols in good yields (up to 84%) and a high level of enantioselectivity (up to
l-tryptophan were prepared and used as organocatalysts in enantioselectiveallylation of aromatic aldehydes with allyltrichlorosilanes. The corresponding addition adducts homoallylic chiral alcohols obtained high enantioselectivities (up to 96% ee) when 1 mol % of catalyst was used. The unexpected result is the addition product's absolute configuration is R when (R)-chiral amides was used, in contrast, it was