Proline-Based <i>N</i>-Oxides as Readily Available and Modular Chiral Catalysts. Enantioselective Reactions of Allyltrichlorosilane with Aldehydes
作者:John F. Traverse、Yu Zhao、Amir H. Hoveyda、Marc L. Snapper
DOI:10.1021/ol050814q
日期:2005.7.1
as an effective catalyst for the reaction of allyltrichlorosilane with aryl and alpha,beta-unsaturated aldehydes at room temperature to afford the desired homoallylic alcohols in up to 92% ee. The chiral catalyst can be easily prepared from optically pure proline in three simple steps and 60% overall yield.
unit with a conformationally rigid chiral backbone has been designed and synthesized in an enantiomerically pure form to utilize in the Lewis base-catalyzed Sakurai–Hosomi–Denmark-type allylation reaction. The chiral pyridine N-oxide in 1:1 mixture of chloroform and 1,1,2,2-tetrachloroethane produced the homoallylic alcohols in up to 98% yield and up to 94% ee.
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.
Asymmetric allylation of aldehydes with allyltrichlorosilane using aza-paracyclophane-oxazoline-N-oxide catalysts
作者:Qiang Chai、Chun Song、Zhijun Sun、Yudao Ma、Chanqin Ma、Yong Dai、Merritt B. Andrus
DOI:10.1016/j.tetlet.2006.09.098
日期:2006.11
chloride followed by m-chloroperbenzoic acid. 4′-Benzyl and tert-butyl-S and R-oxazoline variants were produced and explored as catalysts for asymmetricallylation of aldehydes using trichloroallylsilane. With Rp,S-4a (R = tert-butyl) (1.5 mol %) aromaticaldehydes reacted with high yields and selectivities, as with benzaldehyde (95%, 93% ee). Rp,S-4b (R = benzyl) was superior with dihydrocinnamaldehyde
A New Synthetic Route to Enantiomerically Pure Axially Chiral 2,2‘-Bipyridine <i>N,N</i><i>‘</i>-Dioxides. Highly Efficient Catalysts for Asymmetric Allylation of Aldehydes with Allyl(trichloro)silanes
作者:Toyoshi Shimada、Asato Kina、Tamio Hayashi
DOI:10.1021/jo0300800
日期:2003.8.1
Newaxiallychiral 2,2'-bipyridine N,N'-dioxides 1 were obtained in an enantiomerically pure form by way of cyclic diesters 6 or 7 which were formed by the esterification of diols 2 with (R)-2,2'-bis(chlorocarbonyl)-1,1'-binaphthalene (5). Epimerization of the kinetic products at the ester formation (R(nap),S(pyr))-6 to the thermodynamically stable isomers (R(nap),R(pyr))-7 was observed in refluxing