A Catalyst-Controlled Enantiodivergent Bromolactonization
作者:Yuk-Cheung Chan、Xinyan Wang、Ying-Pong Lam、Jonathan Wong、Ying-Lung Steve Tse、Ying-Yeung Yeung
DOI:10.1021/jacs.1c05680
日期:2021.8.18
enantiodivergent bromolactonization of olefinicacids has been developed. Quinine-derived amino-amides bearing the same chiral core but different achiral aryl substituents were used as the catalysts. Switching the methoxy substituent in the aryl amide system from meta- to ortho-position results in a complete switch in asymmetric induction to afford the desired lactone in good enantioselectivity and yield
strained olefins in trans‐cyclooctenes serve as efficient catalysts for halolactonizations, including bromolactonizations and iodolactonizations. The trans‐cyclooctene framework is essential for excellent catalytic performance, and the substituents also play important roles in determining efficiency. These results are the first demonstration of catalysis by a trans‐cyclooctene.
Reversing the Regioselectivity of Halofunctionalization Reactions through Cooperative Photoredox and Copper Catalysis
作者:Jeremy D. Griffin、Cortney L. Cavanaugh、David A. Nicewicz
DOI:10.1002/anie.201610722
日期:2017.2.13
Halofunctionalization of alkenes is a classical method for olefin difunctionalization. It gives rise to adducts which are found in many natural products and biologically active molecules, and offers a synthetic handle for further manipulation. Classically, this reaction is performed with an electrophilic halogen source and leads to regioselective formation of the halofunctionalized adducts. Herein
Catalytic asymmetric bromolactonization reactions using (DHQD)2PHAL-benzoic acid combinations
作者:Alan Armstrong、D. Christopher Braddock、Alexander X. Jones、Stacy Clark
DOI:10.1016/j.tetlet.2013.10.043
日期:2013.12
Catalytic (DHQD)2PHAL as modified by added benzoic acid, is an off-the-shelf catalyst-additive combination for effecting catalytic asymmetric bromolactonization reactions. This combination delivers bromolactones with asymmetric induction at a comparable level to bespoke catalysts previously optimized for particular substrate classes.
作者:Jørn E. Tungen、Renate Kristianslund、Anders Vik、Trond V. Hansen
DOI:10.1021/acs.joc.9b01294
日期:2019.9.20
A highly efficient and regioselective bromolactonization protocol is reported. The quantitative formation of synthetically versatile bromolactones occurs in the presence of only 0.1 mol % of an organoselenium compound, coined DECAD herein, within 90 min. DECAD is conveniently prepared on multigram scale from cheap racemic camphor. The presented protocol was easy to scale up and performed equally well