Synthesis of New Lansiumamide A/Alatamide (cis‐Isomer) Based Unnatural α‐Amino Acid Derivatives via the Suzuki‐Miyaura Cross Coupling as Key Step

Abstract

We have developed a new synthetic method for the preparation of Lansiumamide-amino acid (1) as well as Alatamide (cisisomer)-amino acid (2) hybrids. The key step involves the Suzuki coupling reaction of N-((Z)-2-bromovinyl) cinnamamide with phenylboronic acid and (Z)-N-(2-iodovinyl)benzamide with 4-methoxy phenylboronic acid. The Suzuki coupling of N-((E)-2bromo-2-phenylvinyl) cinnamamide as well as (E)-N-(2-Iodo-2-(4-methoxyphenyl)vinyl)benzamide with 4-borono-pinacol ester of phenylalanine to give the Lansiumamide-phenylalanine and Alatamide (cis-isomer)-phenylalanine amino acid hybrids in good yields. This is the first synthesis of C-linked Lansiumamide A and Alatamide (cis-isomer)-amino acid conjugates where both the natural products are linked to amino acid through CÀ C bond.

Visible light-induced synthesis of (Z)-β-iodoenamides from N-vinyl amides mediated by the ion pair charge transfer state

“…β-Iodoenamide is a class of useful molecules that can be used as highly functionalized intermediates in organic synthesis, pharmaceutical chemistry, and materials science. 1 In particular, ( Z )-β-iodoenamides are widely employed as key building blocks in the construction of various bioactive compounds and natural products, potential enzyme inhibitors such as β-branched α-amino acids, 2 the marine natural products lituarines B and C, 3 and the anti-inflammatory compound alatamide ( cis -isomer) 4 (Scheme 1). In addition, ( Z )-β-iodoenamides can be applied to acquire diverse heterocyclic compounds such as oxazole and pyrrole.…”

“…12 β-Carbon iodination of N -vinyl amides with suitable reagents should provide the desired β-iodoenamide as a facile and efficient approach; however, this methodology has rarely been reported. 2,4 In recent years, iodide salts, as a class of inexpensive and readily available iodine sources, have been widely used in various iodination reactions, 13 whereas external oxidants such as Selectfluor, persulfates, hypervalent iodine, and hydrogen peroxide are generally required to in situ generate the actual iodinating species in a thermochemical reaction. In such a situation, we are interested in developing a novel and facile synthetic method for ( Z )-β-iodoenamides from N -vinyl amides with inexpensive iodide salts under external-oxidant-free conditions.…”

Iodine and ammonium persulfate mediated activation of DMSO: an approach to N-formylation of amides and synthesis of isatins

“…15 Furthermore, we also carried out the synthesis of the natural product “alatamide” 10 in 47% yield (Scheme 5b). 16…”

“…15 Furthermore, we also carried out the synthesis of the natural product "alatamide" 10 in 47% yield (Scheme 5b). 16 To gain more insight into the reaction pathway, a few control experiments were performed (Scheme 6). A detailed procedure is provided in the ESI †.…”