Asymmetric Total Synthesis of Inthomycins A, B, and C

Abstract

Herein, we report the asymmetric total syntheses of inthomycin antibiotics containing a methylene-interrupted oxazolyl-triene motif. Utilizing the α,β-unsaturated aldehyde as a common intermediate, all three inthomycins A−C were divergently synthesized. The asymmetric ynone reduction provided an R-configured secondary alcohol as in the natural products with high enantioselectivity. The geometrically different triene units for each inthomycin were stereoselectively established via methyl cuprate conjugate addition, isomerization of the α,β-unsaturated aldehyde intermediate, and stereoretentive cross-coupling reactions.

Effect of the Degree of the Gate‐Dielectric Surface Roughness on the Performance of Bottom‐Gate Organic Thin‐Film Transistors

“…Organic thin‐film transistors (TFTs) are promising devices to be employed in future flexible, large‐area electronics applications, such as active‐matrix displays and sensor arrays. [ 1–3 ] The possibility to deposit organic semiconductors at relatively low temperatures makes it possible to fabricate organic TFTs on unconventional substrate materials, such as glass, [ 4,5 ] plastic foils, [ 6–8 ] textiles, [ 9 ] or paper. [ 10,11 ] The use of these substrate materials offers opportunities for a variety of novel applications, but they are usually characterized by a larger surface roughness than conventional substrate materials, and this can have detrimental effects on the performance of the devices.…”

Progress in the total synthesis of inthomycins

“…The elegant work of R. J. K. Taylor [21,43], Ryu [50], Donohoe [57], and Burton [23] demonstrated the power of the Mukaiyama−Kiyooka aldol reactions to install the asymmetric center of inthomycins. Alternatively, Hatakeyama and Kim's groups employed an asymmetric β-lactone synthesis and an asymmetric ynone reduction protocol for the construction of the stereogenic center of inthomycins, respectively [22,24]. Despite these recent advances, the development of novel methods for the regio-and stereocontrolled synthesis of inthomycins, inthomycin-embedded natural products, and their synthetic analogues with better biological outcomes is of strategic importance and being continued for further discovery.…”

“…Since the pioneering works of Henaff and Whiting [19,20], several racemic and asymmetric total syntheses of inthomycins A-C (1-3) have been carried out in many research groups (Figure 2). However, only four synthetic strategies that lead to the total synthesis of all three members of inthomycins A-C (1-3) are available ( Figure 2, route b, d, h, and i) [21][22][23][24].…”

Asymmetric Total Synthesis of Oxazolomycins B and C

“…The selective synthesis of both 31 a and 31 b was described in our previous work on the synthesis of inthomycins. [25] First, the N-Boc group in 30 was removed successfully by treatment with excess TMSOTf, [26] with concomitant silyl protection of hydroxy groups to afford 32. Under other standard acidic N-Boc deprotection conditions, such as TFA, a spiro-tetrahydropyran ring was formed to give 33 prior to cleavage of the Boc group.…”