The Exocyclic Olefin Geometry Control via Ireland–Claisen Rearrangement: Stereoselective Total Syntheses of Barmumycin and Limazepine E

Stereoselective total syntheses of Limazepine E and Barmumycin, potent, naturally occurring antitumor agents, are described. The total syntheses control the olefin geometry via a highly selective chelation-controlled Ireland-Claisen rearrangement of a seven-membered lactone-derived boron enolate for the synthesis of (E)-4-ethylidene proline, a crucial building block for a number of natural products

One-Step Preparation of Pyrrolo[1,4]benzodiazepine Dilactams: Total Synthesis of Oxoprothracarcin, Boseongazepines B and C

A one-step synthesis of pyrrolo[1,4]benzodiazepine dilactams has been developed. The high yielding method involves direct coupling of unprotected anthranilic acids with proline esters. This transformation was successfully applied in the first total syntheses of boseongazepines B and C as well as oxoprothracarcin and limazepine E

The Exocyclic Olefin Geometry Control via Ireland—Claisen Rearrangement: Stereoselective Total Syntheses of Barmumycin (V) and Limazepine E (VI)

The highly selective Ireland—Claisen rearrangement of seven-membered lactone-derived boron enolate generated in situ is the key step to synthesize the naturally occurring antitumor agents (V) and (VI)

Total Synthesis of the Putative Structure of Deoxypumiliotoxin 193H by an Ireland–Claisen Rearrangement

A stereoselective total synthesis of one diastereomer of 8-deoxypumiliotoxin 193H is described. The concise total synthesis features the use of readily available natural amino acids as the starting materials and the Ireland-Claisen rearrangement as the key stereochemistry controlling step. A stereoselective total synthesis of 8-deoxypumiliotoxin 193H is described. The concise total synthesis features the use of readily available starting materials, namely, natural amino acids and the Ireland-Claisen rearrangement as the key stereochemistry controlling step

Late Stage Fe(CO)5 Promoted Double Bond Migration: Total Synthesis of Limazepines C and D

The first total syntheses of limazepines C and D were accomplished from inexpensive and readily available starting materials using an iron pentacarbonyl promoted allylamide-enamide double bond migration as a key step. The obtained limazepine C was found to be unstable and undergoes oxidation to limazepine D

Ireland-Claisen Rearrangement of 6-Methylene-1,4-oxazepan-2-ones

The Ireland-Claisen rearrangement of 6-methylene-1,4-oxazepan-2-one-derived boron enolates leads to stereochemically defined, synthetically useful 4-(E)-ethylidene prolines. Detailed computational and experimental studies explain the stereochemical outcome of this transformation and suggest an unusual double-chelated transition state that involves two boron atoms. The scope of the method is also explored