23543-62-6Relevant articles and documents
Negishi Cross-Coupling Provides Alkylated Tryptophans and Tryptophan Regioisomers
Dachwitz, Steffen,Scharkowski, Bjarne,Sewald, Norbert
supporting information, p. 18043 - 18046 (2021/11/16)
Mild transition-metal catalysed cross-couplings enable direct functionalisation of biocatalytically halogenated tryptophans with alkyl iodides, representing a new alternative for late-stage derivatisations of halogenated aromatic amino acids. Moreover, this strategy enables preparation of (homo)tryptophan regioisomers in a simple two-step synthesis using a Pd-catalysed Negishi cross coupling. This method provides access to non-canonical constitutional surrogates of tryptophan, ready for use in peptide synthesis.
Single-electron transmetalation in organoboron cross-coupling by photoredox/nickel dual catalysis
Tellis, John C.,Primer, David N.,Molander, Gary A.
, p. 433 - 436 (2014/08/05)
The routine application of Csp3-hybridized nucleophiles in cross-coupling reactions remains an unsolved challenge in organic chemistry. The sluggish transmetalation rates observed for the preferred organoboron reagents in such transformations are a consequence of the two-electron mechanism underlying the standard catalytic approach. We describe a mechanistically distinct single-electron transfer-based strategy for the activation of organoboron reagents toward transmetalation that exhibits complementary reactivity patterns. Application of an iridium photoredox catalyst in tandem with a nickel catalyst effects the cross-coupling of potassium alkoxyalkyl- and benzyltrifluoroborates with an array of aryl bromides under exceptionally mild conditions (visible light, ambient temperature, no strong base). The transformation has been extended to the asymmetric and stereoconvergent cross-coupling of a secondary benzyltrifluoroborate.
Tryptamine analogues as 5-ht1-like agonists
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, (2008/06/13)
A compound of structure (I), in which A1 is O, S(O)n in which n is 0, 1 or 2, NR, CH2, or CH(OH); A2 is a bond or CH2 ; or A1 A2 is CH=CH; R is hydrogen or C1-4 alkyl;
