Development of Organoiron Methodology for Preparation of the Polyene Natural Product Macrolactin A

Enhancing production of a 24-membered ring macrolide compound by a marine bacterium using response surface methodology

“…A variant of macrolactin A shows inhibitory activity against the methicillin-resistant Staphylococcus aureus (MRSA) and vancomycinresistant Enterococci (VRE) (Romero-Tabarez et al, 2006). Macrolactin A also exhibits antiviral activity against Herpes Simplex I and II, and against human immunodeficiency virus (HIV) (Bärmann et al, 2000). Unfortunately, the application of macrolactin A is limited due to its low fermentation titers.…”

Stoichiometric Applications of Acyclic π-Organoiron Complexes to Organic Synthesis

“…In contrast to the reactivity of 36, intramolecular nitrile oxide-olefin cyclo-addition for "skipped" triene complex 37 gave an equimolar mixture of diastereomers (eqn. 11) [54]. In this case, the lack of diastereoselectivity may indicate that the steric bulk of the Fe(CO) 3 group is too far distant from the pendent olefin and/or that there is not a preferred reactive conformers about the C-C single bonds.…”

“…Thus, reaction of (1-methoxycarbonylpentadienyl)Fe(CO) 2 PPh 3 + with the anion of ethyl nitroacetate, followed by aqueous workup, gave the (pentenediyl)-Fe(CO) 2 PPh 3 complex 79 as an equimolar mixture of diastereomers (Scheme 18) [54]. In contrast to (pentenediyl)iron complex 77, which is constitutionally stable in solution, (pentenediyl)-iron complex 79 rearranges to (E,Zdiene)iron complex 80 upon standing in CDCl 3 for 1-2 days.…”

“…Prahlad and Donaldson have reported an enantioenriched synthesis of the C11-C24 segment which utilizes organoiron methodology (Scheme 26) [29,54]. This synthesis also begins with racemic 41, however reaction with…”

Enantioselective Synthesis of the C7-C24 Segment of Macrolactin A

“…We have previously reported the preparation of rac-3 and partially resolved 4 (55% ee). 6 Herein we report the enantioselective synthesis of (+)-3 and (+)-4, their coupling via an intermolecular nitrile oxide-olefin cycloaddition, and eventual elaboration into 2b, constituting the C7-C24 segment of macrolactin A.…”