1,3-Asymmetric induction in the intramolecular [2+2] cycloaddition of alkene-keteniminium salts. Synthesis of (+)-gibberellic acid key intermediate

Shim, Pil-Jong; Kim, Hee‐Doo

doi:10.1016/s0040-4039(98)02228-x

Cited by 22 publications

(14 citation statements)

References 16 publications

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“…Unfortunately, low yields were observed for the cycloaddition and a low regioselectivity ratio for the ring expansion of approximately 2 : 1 was detected. 39…”

Section: Development Of the Methodologymentioning

confidence: 99%

Amide activation: an emerging tool for chemoselective synthesis

et al. 2018

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It is textbook knowledge that carboxamides benefit from increased stabilisation of the electrophilic carbonyl carbon when compared to other carbonyl and carboxyl derivatives. This results in a considerably reduced reactivity towards nucleophiles. Accordingly, a perception has been developed of amides as significantly less useful functional handles than their ester and acid chloride counterparts. However, a significant body of research on the selective activation of amides to achieve powerful transformations under mild conditions has emerged over the past decades. This review article aims at placing electrophilic amide activation in both a historical context and in that of natural product synthesis, highlighting the synthetic applications and the potential of this approach.

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“…Unfortunately, low yields were observed for the cycloaddition and a low regioselectivity ratio for the ring expansion of approximately 2 : 1 was detected. 39…”

Section: Development Of the Methodologymentioning

confidence: 99%

Amide activation: an emerging tool for chemoselective synthesis

et al. 2018

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“…在此, 我们选取该类反应较为重要的发展节点, 简明扼要的阐述其发展历程, 总结此类反应的规律和特点. [35] 、赤霉酸中间体 75 [36] 、前列腺素内酯(76) [37] 及 3-酰基取代的环丁酮螺环化合物 77 [38] (图 2). Figure 19 Unexpected discovery of cyclization/Claisen rearrangement 随后的研究发现, 除烯丙基以外, 其他能够稳定碳正离子的取代基如炔丙基、苄基、2-四氢呋喃基、2-四氢吡喃基等都能参与上述亲电重排反应, 制备一系列 α-烷基取代的内酯化合物 [45,46] (Scheme 20).…”

Section: [2＋2]环加成反应unclassified

Recent Progress in the Chemistry of Keteniminium Salts

Li¹,

Sun²,

Zhang³

et al. 2016

Chin. J. Org. Chem.

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Keteniminium salts are unique heteroallenes. The high electrophility and cumulative double bonds render them versatile reactivity. This paper describes the keteniminium salts formed by electrophilic activation of amides or ynamides with non-metal electrophilic reagents. These keteniminium salts mainly undergo electrophilic addition, eletrophilic substitution, cycloaddition with various nucleophiles. In past few years, the study of keteniminium induced electrophilic rearrangement has progressed rapidly. The newly developed rearrangement transformations are also described here.

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“…6). Under these conditions, complete consumption of the iodo starting material was observed, yielding the desired product [14] in a respectable 78 % yield accompanied by 12 % of the formal elimination by-product. [15] The use of a lower reaction temperature or shorter residence time yielded incomplete conversion, which is also in accordance with the expected half-life and thus activity of the radical initiator 2,2 0 -azobis(2methylpropionitrile) (AIBN).…”

Section: Modification Of the Reactor Insert For More Effective Heatingmentioning

confidence: 99%

Flow Microwave Technology and Microreactors in Synthesis

et al. 2013

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A bespoke microwave reactor with a glass containment cell has been developed for performing continuous flow reactions under microwave heating. The prototype unit has been evaluated using a series of standard organic chemical transformations enabling scale-up of these chemical processes. As part of the development, a carbon-doped PTFE reactor insert was utilized to allow the heating of poorly absorbing reaction media, increasing the range of solvents and scope of reactions that can be performed in the device.

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1,3-Asymmetric induction in the intramolecular [2+2] cycloaddition of alkene-keteniminium salts. Synthesis of (+)-gibberellic acid key intermediate

Cited by 22 publications

References 16 publications

Amide activation: an emerging tool for chemoselective synthesis

Amide activation: an emerging tool for chemoselective synthesis

Recent Progress in the Chemistry of Keteniminium Salts

Flow Microwave Technology and Microreactors in Synthesis

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