Iridium-Catalyzed Triborylation of 3-Substituted Indoles

Eastabrook, Andrew S.; Sperry, Jonathan

doi:10.1071/ch15393

Cited by 11 publications

(8 citation statements)

References 14 publications

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“… [119] With higher stoichiometries of B 2 pin 2 , iterative borylation of 3‐substituted indoles such as 3‐methylindole ( 136 ) can occur, with C−H activation occurring at, successively, C‐2, C‐7, and C‐5 (Scheme 15 g). [120] Formal selective C‐7 mono‐borylation of indole is possible by blocking C‐2 with a labile group, which is subsequently removed. For example, a 2‐silyl substituent can be selectively cleaved using TBAF after having sterically directed borylation to C‐7 (Scheme 15 h).…”

Section: Borylation Of Heteroarenesmentioning

confidence: 99%

Iridium‐Catalysed C−H Borylation of Heteroarenes: Balancing Steric and Electronic Regiocontrol

2020

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Section: Borylation Of Heteroarenesmentioning

confidence: 99%

Iridium‐Catalysed C−H Borylation of Heteroarenes: Balancing Steric and Electronic Regiocontrol

2020

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“…To complete the SAR study, we decided to synthesize and test a triply arylated Trp derivative whose obtention would be accomplished through a convergent synthetic strategy similar to that described above ( Scheme 4 ). The key intermediate in this route was triply arylated Trp derivative 35 , which was obtained through an SMR between the crude organoboron Trp intermediate 34 , 48 bearing three Bpin substituents at the C2/C5/C7 positions, and isophthaloyl bromide. Subsequent removal of the Boc-protecting group afforded amino intermediate 36 .…”

Section: Results and Discussionmentioning

confidence: 99%

Double Arylation of the Indole Side Chain of Tri- and Tetrapodal Tryptophan Derivatives Renders Highly Potent HIV-1 and EV-A71 Entry Inhibitors

et al. 2021

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We have recently described a new generation of potent human immunodeficiency virus (HIV) and EV-A71 entry inhibitors. The prototypes contain three or four tryptophan (Trp) residues bearing an isophthalic acid moiety at the C2 position of each side-chain indole ring. This work is now extended by both shifting the position of the isophthalic acid to C7 and synthesizing doubly arylated C2/C7 derivatives. The most potent derivative (50% effective concentration (EC 50 ) HIV-1, 6 nM; EC 50 EV-A71, 40 nM), 33 ( AL-518 ), is a C2/C7 doubly arylated tetrapodal compound. Its superior anti-HIV potency with respect to the previous C2-arylated prototype is in consonance with its higher affinity for the viral gp120. 33 ( AL-518 ) showed comparable antiviral activities against X4 and R5 HIV-1 strains and seems to interact with the tip and base of the gp120 V3 loop. Taken together, these findings support the interest in 33 ( AL-518 ) as a useful new prototype for anti-HIV/EV71 drug development.

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“…This desired transformation aligns perfectly with the iridium-catalyzed C-H borylation reaction, 15 the regiochemical outcome of which is reliably dictated by the directing ability of the indole N-H. Subjecting 1 to an iridium-catalyzed C-H borylation using the 3,4,7,8-tetramethylphenanthroline as ligand (Me4Phen) 16,17 gave the 7-borylindole 9 in good yield. A DMAP-assisted 18 Chan-Evans-Lam coupling of 9 with methanol gave the natural product 5,7-dimethoxy-2,4-dimethylindole (3).…”

mentioning

confidence: 90%