Total Synthesis of (−)-Virginiamycin M₂ Using Second-Generation Vinylogous Urethane Chemistry

Efficient synthesis of allylamines from a novel (E)-2,3-difunctionalized allyl bromide

“…It should be noted that the synthesis of allyl bromide 4 was always accompanied by the formation of its regioisomer 5, which was easily separable from the desired product 4 by silica gel column chromatography (Scheme 3). In order to establish a chemical library reserved for the various functionalized allylamines published during the last decade by our research group 30 and their use as basic skeletons of many biologically important substances [31][32][33][34][35][36][37] and numerous natural products [38][39][40][41][42][43][44][45][46][47] , we focused our attention on the synthesis of a new family of allylamines 6. The best reaction conditions were obtained following the reaction of the electrophilic allyl bromide (E)-4 with excess of monoalkylamines (2 equiv.)…”

A Flexible Approach to Azasugars: Asymmetric Total Syntheses of (+)‐Castanospermine, (+)‐7‐Deoxy‐6‐epi‐castanospermine, and (+)‐1‐epi‐Castanospermine

“…Further elaboration of compounds 9 to 5-alkyl-4-hydroxyl-2-pyrrolidinones 11 via the corresponding 5-alkyltetramic acids 10 validated compound 8 as a synthetic equivalent of chiral synthons D and A. [26] More recently, we reported preliminary results on the highly diastereoselective C-5 a-hydroxyalkylation of 8 and application of this method to the asymmetric synthesis of 3.…”

“…[19a,b] In connection with a program aimed at the synthesis of 5-alkylteramic acids and 5-alkyltetramates, which are also key structural features found in many bioactive natural products, [24,25] we have been engaged in the development of enantiomerically pure tetramic acid derivative 8 as a synthetic equivalent of tetramic acid synthon D and 4-hydroxyl-2-pyrrolidinone 5-carbanionic synthon A (Scheme 2). [26,27] By starting from this building block, a highly diastereoselective and C-5 regioselective alkylation method was established for the synthesis of 5-alkyltetramic acid derivatives 9. Further elaboration of compounds 9 to 5-alkyl-4-hydroxyl-2-pyrrolidinones 11 via the corresponding 5-alkyltetramic acids 10 validated compound 8 as a synthetic equivalent of chiral synthons D and A.…”

Total synthesis of antibiotics: recent achievements, limitations, and perspectives

“…(Barrière 1993(Barrière , 1994 The structure of virginiamycin was established by X-ray crystallography in 1974, however, due to the presence of pH sensitive -hydroxyketone moiety, the first total synthesis of this natural product was achieved more than twenty year later. (Schlessinger, 1996) Recently, a very concise synthesis of virginiamycin M 2 was accomplished by Panek group. Their strategy relied on the intamolecular Barbier/Reformatsky type reaction and low-valent Ti-mediated reductive alkyne-alkyne coupling as a key steps.…”