Cobalt(III)-Catalyzed C-6 Alkenylation of 2-pyridones by using Terminal Alkyne with High Regioselectivity

We report selective formation of heterobimetallic PtII/CuI complexes that demonstrate how facile bond activation processes can be achieved by altering reactivity of common organoplatinum compounds through their interaction with another metal center. The interaction of the Cu center with Pt center and with a Pt-bound alkyl group increases the stability of PtMe2 towards undesired rollover cyclometalation. The presence of the CuI center also enables facile transmetalation from electron-deficient tetraarylborate [B(ArF)4]- anion and mild C-H bond cleavage of a terminal alkyne, which was not observed in the absence of an electrophilic Cu center. The DFT study indicates that the role of Cu center acts as a binding site for alkyne substrate, while activating its terminal C-H bond.

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Probing the Versatility of Shape-Persistent Tetraphenylmethane Dendrimers by Modification of the Skeleton

10.26434/chemrxiv.9947054 ◽

2019 ◽

Author(s):

Julio Ignacio Urzúa ◽

Sandra Campana ◽

Massimo Lazzari ◽

Mercedes Torneiro

Keyword(s):

Design Principle ◽

Focal Point ◽

Sonogashira Coupling ◽

Terminal Alkyne ◽

Double Phase ◽

Rigid Rod ◽

Convergent Approach ◽

First And Second Generation ◽

Oxidative Homocoupling ◽

Hypercrosslinked Polymers

Tetraphenylmethane has emerged as a recurrent building block for advanced porous materials such as COFs, PAFs and hypercrosslinked polymers. Guided by a similar design principle, we have previously synthesized shape-persistent dendrimers with tetraphenylmethane nodes and ethynylene linkers. Here we report the generality of our approach by describing new dendritic architectures built from tetraphenylmethane. First, we prepared expanded dendrimers where the tetrahedral units are bonded through larger rigid rod spacers. Among the different synthetic strategies tested, the convergent route, with alternating steps of Pd-catalyzed Sonogashira coupling and alkyne activation by removal of TMS masking groups, efficiently afforded the first- and second-generation dendrimers. A second type of compounds having a linear diyne at the core is also described. The dendrimers of generations 1-2 were also synthesized by a convergent approach, with the diyne being assembled in the last step of the synthesis by a Glaser oxidative homocoupling of the corresponding dendrons bearing a terminal alkyne at the focal point. A third-generation dendrimer was also successfully prepared by a double-phase strategy.<br>

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Faculty Opinions recommendation of Discovery of a pathway for terminal-alkyne amino acid biosynthesis.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.735314077.793558905 ◽

2019 ◽

Author(s):

Sheila David

Keyword(s):

Amino Acid ◽

Amino Acid Biosynthesis ◽

Terminal Alkyne ◽

Acid Biosynthesis

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Faculty Opinions recommendation of Discovery of a pathway for terminal-alkyne amino acid biosynthesis.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.735314077.793558608 ◽

2019 ◽

Author(s):

Ikuro Abe ◽

Takahiro Mori

Keyword(s):

Amino Acid ◽

Amino Acid Biosynthesis ◽

Terminal Alkyne ◽

Acid Biosynthesis

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Convenient Synthesis of (Z)-7- and (E)-9-dodecene-1-yl Acetate, Components of Some Lepidoptera Insect Sex Pheromone

Revista de Chimie ◽

10.37358/rc.17.1.5415 ◽

2017 ◽

Vol 68 (1) ◽

pp. 180-185

Author(s):

Adriana Maria Andreica ◽

Lucia Gansca ◽

Irina Ciotlaus ◽

Ioan Oprean

Keyword(s):

Sex Pheromone ◽

Coupling Reaction ◽

Coupling Scheme ◽

Lithium Aluminium Hydride ◽

Terminal Alkyne ◽

Mercury Derivative ◽

Lithium Aluminium ◽

Convenient Synthesis ◽

Practical Synthesis ◽

Insect Sex

Were developed new and practical synthesis of (Z)-7-dodecene-1-yl acetate and (E)-9-dodecene-1-yl acetate. The routes involve, as the key step, the use of the mercury derivative of the terminal-alkyne w-functionalised as intermediate. The synthesis of (Z)-7-dodecene-1-yl acetate was based on a C6+C2=C8 and C8+C4=C12 coupling scheme, starting from 1,6-hexane-diol. The first coupling reaction took place between 1-tert-butoxy-6-bromo-hexane and lithium acetylide-ethylendiamine complex obtaining 1-tert-butoxy-oct-7-yne, which is transformed in di[tert-butoxy-oct-7-yne]mercury. The mercury derivative was directly lithiated and then alkylated with 1-bromobutane obtaining 1-tert-butoxy-dodec-7-yne. After acetylation and reduction with lithium aluminium hydride of 7-dodecyne-1-yl acetate gave (Z)-7-dodecene-1-yl acetate with 96 % purity. The synthesis of (E)-9-dodecene-1-yl acetate was based on a C8+C2=C10 and C10+C2=C12 coupling scheme, starting from 1,8-octane-diol. The first coupling reaction took place between 1-tert-butoxy-8-bromo-octane and lithium acetylide-ethylendiamine complex obtaining 1-tert-butoxy-dec-9-yne, which is transformed in di[tert-butoxy-dec-9-yne]mercury. The mercury derivative was directly lithiated and then alkylated with 1-bromoethane obtaining 1-tert-butoxy-dodec-9-yne. After reduction with lithium aluminium hydride of 1-tert-butoxy-(E)-9-dodecene and acetylation was obtained (E)-9-dodecene-1-yl acetate with 97 % purity.

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