C–O cleavage via InIII alkoxide intermediates: In situ 13C NMR analysis of the mechanism of an enantioselective in-mediated cyclopropanation reaction
作者:Jennifer L. Slaughter、Guy C. Lloyd-Jones
DOI:10.1016/j.tet.2020.131786
日期:2021.1
dibenzylideneacetone and benzylideneacetone by in situ generated allyl indium reagents in the presence of methyl mandelate as a chiral modifier has been studied by in situ 13C1H} NMR in conjunction with 13C/2H labelling and mass spectrometry. Two indium alkoxides were identified, the first arising from indium mediated allylation of the ketone, the second arising from reaction of an in situ liberated
通过原位13 C 1 H} NMR结合13 C / 2 H标记和质量研究了原位生成的烯丙基铟在手性改性剂存在下通过原位生成的烯丙基铟试剂对二苄叉基丙酮和苄叉基丙酮进行不对称环丙烷化的机理。光谱法。鉴定出两种铟醇盐,第一种是由铟介导的酮的烯丙基化产生的,第二种是由LiI介导的原位释放的均烯丙基与过量的烯丙基铟试剂的反应产生的。在酸化过程中,氧的质子化导致C–O而不是In–O裂解,并且初始的叔烯丙基阳离子被约90%的si立体选择性烯丙基化 通过假定为扁桃酸酯螯合的铟烯丙基试剂进行选择性。
Tandem Anionic oxy‐Cope Rearrangement/Oxygenation Reactions as a Versatile Method for Approaching Diverse Scaffolds
Tandem anionic oxy‐Coperearrangement/radical oxygenation reactions provide δ,ϵ‐unsaturated α‐(aminoxy) carbonyl compounds, which serve as convenient precursors to diverse compound classes. Functionalized carbocycles are accessible by very rare all‐carbon 5‐endo‐trig cyclizations, but also common 5‐exo‐trig radical cyclizations, based on the persistent radical effect. The tandem reactions can be further