Stereoselective synthesis of (3S,5S,6S)-tetrahydro-6-isopropyl-3,5-dimethylpyran-2-one; a C5-epimer of a component of a natural sex pheromone of the wasp Macrocentrus grandii, the larval parasitoid of the European corn borer Ostrinia nubilalis

Selective Carbon–Carbon Bond Cleavage of Cyclopropanols

“…The authors reported that both cyclopropyl mesylates and tosylates work in this protocol, and the scope of the Lewis acid includes MgBr 2 , MgCl 2 , AlCl 3 , and TiCl 4 . This methodology has found repeated use in the early steps of several natural products syntheses, such as epothilone A, (+)-neopeltolide, neolaulimalide, amphidinolides B1, and their corresponding building blocks (Scheme b). − …”

Recent advances in the application of the Oppolzer camphorsultam as a chiral auxiliary

“…The first stereoselective synthesis of (3S,5S,6S)-tetrahydro-6-isopropyl-3,5-dimethylpyran-2-one 41 was achieved from the easily available natural amino acid L-valine 43 via the work of Matiushenkov et al, 35 in which the C2-C3 carbon fragment of lactone 41 was created via a diastereoselective alkylation of Oppolzer's N-acylsultam. 36 The diastereoselective alkylation of the sodium enolate obtained from Oppolzer's N-propionylsultam 45 with the alkyl bromide 44 with HMPTA and TBAI 36 provided imide 46.…”

New synthesis of syn-stereodiad building block for polyketides. Formal synthesis of arenamides A and C

“…Taking into account broad spectrum of biological activity of arenamides and keen interest of our research team in total and formal syntheses of natural compounds from hydroxy esters [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31], a novel procedure has been developed for the preparation of protected (3S,4S)-3-hydroxy-4-methyldecanoic acid 2 which is the most complex molecular fragment of macrolides 1a-1c (Scheme 1). The starting compound for the synthesis of 2 was (7S)-7-(3-bromoprop-1-en-2-yl)-5,5-dimethyl-4,6-dioxaspiro [2.5]octane (4).…”