Enantiospecific Formal Synthesis of Inthomycin C

Abstract

An enantiospecific synthesis of Hatakeyama's intermediate enynol has been accomplished in both enantiomeric forms. As these intermediates can be converted to (3R)‐inthomycin C and (3S)‐inthomycin C through respective enynol intermediates using reported procedures, present effort may be regarded as formal synthesis of inthomycin C in both enantiomeric forms. Our synthesis highlights the use of pantolactone chiral pool and thus reconfirms the previously assigned absolute stereochemistry as 3R to the natural product inthomycin C.

Asymmetric Total Synthesis of (−)-(3R)-Inthomycin C

“…To date, there have been four reported asymmetric total syntheses of inthomycin C by Taylor, Ryu, Hatakeyama and Hale . Additionally, a formal synthesis of racemic material has been reported by Maulide, and an asymmetric formal synthesis has been reported by Reddy . Recently, Hale and Hatakeyama jointly confirmed the absolute configuration of (−)-(3 R )-inthomycin C by collaboration .…”

“…10 Additionally, a formal synthesis of racemic material has been reported by Maulide, 11 and an asymmetric formal synthesis has been reported by Reddy. 12 Recently, Hale and Hatakeyama jointly confirmed the absolute configuration of (−)-(3R)-inthomycin C by collaboration. 13 It is noteworthy that all published syntheses of (−)-(3R)-inthomycin C (ranging between 11−16 steps) rely on a Stille cross-coupling reaction to form the C7−C8 bond and differ in their approach toward the synthesis of the β-hydroxyl carbonyl moiety.…”

Progress in the total synthesis of inthomycins

“…Two years later, Reddy and co-workers accomplished enantiospecific formal syntheses of both inthomycins C ((+)- 3 ) and inthomycin C ((−)- 3 ) using Hatakeyama’s enynol intermediate 82b ( Scheme 15 ) [ 66 ]. The synthesis commenced with the benzylation of ( R )-pantolactone 108a to produce (+)- 109a in 85% yield.…”

“…Hatakeyama groups demonstrated that inthomycin C ((-)-3) has (3R)-and not (3S)-stereochemistry [57]. Careful reappraisal of the previously published work [21,22,50,60] [66]. The synthesis commenced with the benzylation of (R)-pantolactone 108a to produce (+)-109a in 85% yield.…”

Conjugated Polymer /Multi Wall Carbon Nanotubes Composite Characterisation for Application in Volatile Organic Compounds Sensors

“…As reported by Kulkarni, the sensing performances of PANI to ethanol vapour were significantly improved upon inclusion of small concentrations of silver (Ag) nanoparticles. However, the PANI/Ag nanocomposite sensor exhibited poor response and inferior reproducibility [9][10].…”