Construction of Homoallylic Alcohols from Terminal Alkynes and Aldehydes with Installation of syn-Stereochemistry
摘要:
A cationic rhodium(I) catalyst turns 2-silyl-1-alkenylboronate, readily prepared from a terminal alkyne, into the corresponding allylboronate species, which immediately undergoes nucleophilic addition to an aldehyde to give a syn-homoallylic alcohol stereoselectively.
Barbier-Type Allylation of Aldehydes and Ketones with Metallic Lead in Aqueous Media
作者:Jing-Yao Zhou、Yu Jia、Guang-Fu Sun、Shi-Hui Wu
DOI:10.1080/00397919708006791
日期:1997.6
Abstract Homoallylic alcohols can be obtainedfromallylation of aldehydes and ketones with allyl bromide promoted by metallic lead. These reactions can be carried out smoothly in aqueous media.
摘要 醛和酮与烯丙基溴在金属铅的促进下烯丙基化可制得高烯丙醇。这些反应可以在水性介质中顺利进行。
An efficient Bi/NH4I-mediated addition reaction for the highly diastereoselective synthesis of homoallylic alcohols in aqueous media
Abstract An efficient water-based bismuth-mediated addition reaction of carbonyl compound with cyclic allylic halide was developed. The reactions proceeded smoothly in aqueous DMF in the presence of ammonium iodide to afford the corresponding syn -homoallylic alcohols in moderate to good yields with excellent diastereoselectivities (>99:1 syn : anti ). Reversal of product diastereoselectivity was observed
reactions of carbonylcompounds with cyclic allylic halides in the presence of stoichiometric amounts of lithium chloride and a catalytic amount of GaCl3 (20 mol %), leading to the desired homoallylic alcohols in modest to high yields with excellent diastereocontrol (>99:1 syn/anti) and good functional group tolerance. In contrast, the use of either 2-pyridinecarboxaldehyde as the carbonyl substrate or
发现在化学计量的氯化锂和催化量的GaCl 3(20 mol%)存在下,铅有效地介导了羰基化合物与环状烯丙基卤化物的烯丙基化反应,从而以中等收率和高收率得到了所需的均丁醇。出色的非对映控制(> 99:1 syn / anti)和良好的官能团耐受性。相反,使用2-吡啶羧醛作为羰基底物或使用(E)-肉桂基溴化物作为烯丙基化剂产生具有相反的非对映选择性(> 99:1抗/ syn)的相应产物。
Catalytic Allylation of Aldehydes Using Unactivated Alkenes
作者:Shun Tanabe、Harunobu Mitsunuma、Motomu Kanai
DOI:10.1021/jacs.0c04735
日期:2020.7.15
and a chromium complex catalyst, enabling catalytic allylation of aldehydes with simplealkenes, including feedstock lower alkenes. The reaction proceeded under visible-light irradiation at room temperature and with high functional group tolerance. The reaction was extended to an asymmetric variant by employing a chiral chromium complex catalyst.
diastereoselective. The allylation of benzaldehyde by 1-chlorobut-2-ene in 1,3-dimethylimidazolidin-2-one (DMI) does not occur with tin(II) chloride or bromide but does proceed with tin(II) iodide and exhibits gamma-syn selectivity which is unusual for a Barbier-type carbonylallylation. In the carbonylallylation by 1-chlorobut-2-ene with any tin(II) halide, the addition of tetrabutylammoniumiodide (TBAI) accelerates