Total Synthesis of Spirastrellolide F Methyl Ester—Part 1: Strategic Considerations and Revised Approach to the Southern Hemisphere

Total Synthesis of Spirastrellolide F Methyl Ester—Part 2: Macrocyclization and Completion of the Synthesis

“…In accord with our model studies, [7] addition of aqueous NaOH to the resulting borane 7 generated a suitable borate nucleophile that readily engaged in a palladium-catalyzed cross-coupling reaction with the elaborate triflate 6. After an oxidative work up with basic H 2 O 2 to remove all boron impurities, the desired seco-acid 8 was isolated in a respectable 75 % yield.…”

“…As outlined in the previous communication, this redesign led to a synthesis blueprint that envisages a highly convergent access to the macrocyclic core 4 (Scheme 1). [7] In an attempt to streamline this critical manoeuvre and reduce any late-stage manipulation of protecting groups to a minimum, [8] we devised an expeditious route to compound 6 as a surrogate of the southern hemisphere that carries an enol triflate and a free carboxylic acid at its termini. An alkyl-Suzuki cross coupling reaction [9] and a lactonization event should join this fragment to the northern sector 5, for which a highly productive and scalable synthesis had already previously been worked out.…”

Xylapyrrosides A and B, two rare sugar-morpholine spiroketal pyrrole-derived alkaloids from Xylaria nigripes: isolation, complete structure elucidation, and total syntheses

“…Oxidation 22 of the alcohol 13 with DessMartin periodinane (DMP) furnished the ketone 14 in 92% yield. The precursor 14 underwent an intramolecular spiroketalization 10,23 in the presence of moderate acidic conditions to deliver a mixture of compounds 1, 2 and 4, together with another three new diastereoisomers (1a, 1b and 2a) ( Figure 1 and Scheme 2). Separation of the above six diastereoisomeric spiro-alkaloids was successfully achieved by repeated chromatography on silica gel and followed by semi-preparative HPLC ( Figure 5).…”

Spirastrellolide E: synthesis of an advanced C(1)–C(24) southern hemisphere

“…The combination of structural complexity, biological activity, and, at the outset, unknown relative stereochemistry led to considerable interest in the synthetic community, 5–27 culminating in the first total synthesis of spirastrellolide A (2008) by the Paterson 28–31 group, and the total syntheses of spirastrellolide F (2009, 2011) 32–34 and later A (2013), 35 both by Furstner and colleagues.…”