Recent applications of Cp₂TiCl in natural product synthesis

Abstract

Titanocene(iii)-based approaches have been demonstrated to be useful in the straightforward syntheses of many natural products from readily available starting materials.

Titanium carbenoid-mediated cyclopropanation of allylic alcohols: selectivity and mechanism

“…2,3 Many approaches to the synthesis of the cyclopropane ring have been reviewed. 7 Esters, ketones, amides and other carbonyl compounds can be methylated using three different titanium-based reagents: the Tebbe reagent, titanocyclobutanes and dimethyltitanocene. A number of modifications of the original zinc-copper couple based Simmons-Smith methodology have recently been reported.…”

Recent developments in transition-metal photoredox-catalysed reactions of carbonyl derivatives

“…In order to address these issues, a number of reductive coupling reactions of carbonyl derivatives involving a catalytic amount of early transition (e.g., Ti, V) or lanthanide metals (e.g., Sm) have been developed over the years and applied in natural product synthesis. 3, 33-38 Nonetheless, complementary strategies to generate ketyl and α-aminoalkyl anion radical intermediates and to harness their unusual reactivity are still highly sought after.…”

Total Syntheses of Rhodomolleins XX and XXII: A Reductive Epoxide‐Opening/Beckwith–Dowd Approach

“…Initially,w ea ssumed that the bicyclo[3.2.1]octane carbon framework of 5 and 6 could be built up from vinylphenol 8 according to our previously developed ODI-[5+ +2] cascade (path a). Accordingly,atitanium(III)-mediated reductive ring-opening of [2.2.2] bicyclic keto-epoxide 12 generates 11, [11] which would undergo subsequent Beckwith-Dowd rearrangement [12] through the intermediacyo fc yclopropoxy radical 10 to forge the desired bicyclo[3.2.1]octane ring of the molecules. Based on the elegant work of Baran [9a] and Mori, [9b] an alternative strategy relying on the regioselective fragmentation of an excessively functionalized intermediate [10] was proposed (path b).…”