A new synthesis of phthalides by internal trapping in ortho-lithiated carbamates derived from benzylic alcohols
摘要:
The addition of t-BuLi to a low-temperature THF solution of o-bromocarbamates 2 leads to ortho-lithiated intermediates 3, in which internal trapping by the electrophile on the side chain then takes place. This novel Parham-type anionic cyclization procedure affords the variously substituted phthalides 5 in high yields and can also be used for the preparation of lactones 8, which are useful for the synthesis of aristocularine alkaloids.
Selective acetylation of primary alcohols by ethyl acetate
作者:Raju Singha、Jayanta K. Ray
DOI:10.1016/j.tetlet.2016.10.088
日期:2016.11
A KOtBu and ethyl acetate mediated efficient methodology has been developed for the acetylation of primary and secondaryalcohols where ethyl acetate is the source of acetyl group. The reaction is fast, mild, efficient, and highly selective towards the primary alcohols.
已经开发了用于叔和仲醇的乙酰化的KO t Bu和乙酸乙酯介导的有效方法,其中乙酸乙酯是乙酰基的来源。该反应对伯醇快速,温和,有效且高度选择性。
The addition of t-BuLi to a low-temperature THF solution of o-bromocarbamates 2 leads to ortho-lithiated intermediates 3, in which internal trapping by the electrophile on the side chain then takes place. This novel Parham-type anionic cyclization procedure affords the variously substituted phthalides 5 in high yields and can also be used for the preparation of lactones 8, which are useful for the synthesis of aristocularine alkaloids.
An Enantioselective Suzuki–Miyaura Coupling To Form Axially Chiral Biphenols
作者:Robert Pearce-Higgins、Larissa N. Hogenhout、Philip J. Docherty、David M. Whalley、Padon Chuentragool、Najung Lee、Nelson Y. S. Lam、Thomas M. McGuire、Damien Valette、Robert J. Phipps
DOI:10.1021/jacs.2c06529
日期:2022.8.24
derives its chirality from an atropisomeric axis that is introduced through sulfonation. We believe that attractive noncovalent interactions involving the ligand sulfonate group are responsible for the high levels of asymmetricinduction that we obtain in the 2,2′-biphenol products of Suzuki–Miyaura coupling, and we have developed a highly practical resolution of sSPhos viadiastereomeric salt recrystallization