Abstract
Organolithium compounds have been at the forefront of synthetic chemistry for over a century, as they mediate the synthesis of myriads of compounds that are utilised worldwide in academic and industrial settings. For that reason, lithium has always been the most important alkali metal in organometallic chemistry. Today, that importance is being seriously challenged by sodium and potassium, as the alkali‐metal mediation of organic reactions in general has started branching off in several new directions. Recent examples covering main‐group homogeneous catalysis, stoichiometric organic synthesis, low‐valent main‐group metal chemistry, polymerization, and green chemistry are showcased in this Review. Since alkali‐metal compounds are often not the end products of these applications, their roles are rarely given top billing. Thus, this Review has been written to alert the community to this rising unifying phenomenon of “alkali‐metal mediation”.
Highlights
Organolithium compounds have been at the forefront of synthetic From the Contents chemistry for over a century, as they mediate the synthesis of myriads of compounds that are utilised worldwide in academic and industrial 1
That importance is Mediated Applications being seriously challenged by sodium and potassium, as the alkalimetal mediation of organic reactions in general has started branching 3
Representative reactions in ethereal/eutectic mixtures in the presence of air and moisture: a) nucleophilic additions of organometallic reagents to ketones, b) ortho-lithiation and nucleophilic acyl substitution of a benzamide derivative, and c) organolithium-promoted anionic polymerization of olefins. In this Review we have tried to paint a picture of the increasing utilisation of organoalkali-metal compounds in mediating new chemistry for a diverse range of applications
Summary
With more and more chemists and funding agencies understandably placing greater emphasis on the sustainable future of our planet, research into terrestrially abundant, inexpensive, and non-toxic elements is gathering momentum. Chemie and 24 s and a combined flow rate of 10 mL minÀ1 With these substrates, potassium–hydrogen exchange occurs selectively on the aryl ring, and the potassiated intermediates can undergo immediate electrophilic interception with, for example, aldehydes, ketones, alkyl and allylic halides, and disulfides, to produce the target functionalized (hetero)arenes in high yields. Potassium–hydrogen exchange occurs selectively on the aryl ring, and the potassiated intermediates can undergo immediate electrophilic interception with, for example, aldehydes, ketones, alkyl and allylic halides, and disulfides, to produce the target functionalized (hetero)arenes in high yields The scope of these KDA(TMEDA)-mediated reactions is extended to the lateral potassiation of methylsubstituted (hetero)arenes to generate, in turn, benzylic potassium intermediates and methyl-functionalised heteroarenes, as illustrated with toluene in Scheme 12. X-ray diffraction studies (the molecular structure of the potassium carboenoid is depicted in Figure 3) revealed a significant weakening of the CÀCl bond, as evidenced by its elongation compared to the bond in the precursor (by 0.05 for Na, 0.03 for K).[32b]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
