Synthesis of an insecticidal tetrahydroisocoumarin, (3R,4S,4aR)-4,8-dihydroxy-3-methyl-3,4,4a,5-tetrahydro-1H-2-benzopyran-1-one
摘要:
The insecticidal tetrahydroisocoumarin, (3R,4S,4aR)-4,8-dihydroxy-3-methyl-3,4,4a,5-tetrahydro-1H-2-benzopyran-1-one, was synthesized as a racemate and as an optically active form using one-potesterification-Michael addition-aldol reaction of delta-hydroxy-alpha,beta-unsaturated aldehyde and diketene as a key step. (c) 2006 Elsevier Ltd. All rights reserved.
Scope and Limitations of 2-Deoxy- and 2,6-Dideoxyglycosyl Bromides as Donors for the Synthesis of β-2-Deoxy- and β-2,6-Dideoxyglycosides
作者:Miho Kaneko、Seth B. Herzon
DOI:10.1021/ol501101f
日期:2014.5.16
It is shown that 2-deoxy- and 2,6-dideoxyglycosyl bromides can be prepared in high yield (72–94%) and engaged in glycosylation reactions with β:α selectivities ≥6:1. Yields of product are 44–90%. Fully armed 2-deoxyglycoside donors are viable, while 2,6-dideoxyglycosides require one electron-withdrawing substituent for high efficiency and β-selectivity. Equatorial C-3 ester protecting groups decrease
Intramolecular conjugate addition of γ- and δ-trichloroacetimidoyloxy-α,β-unsaturated esters in an acyclic system
作者:Yoshitaka Matsushima、Jun Kino
DOI:10.1016/j.tet.2008.02.061
日期:2008.4
An intramolecular conjugate addition of γ- and δ-trichloroacetimidoyloxy-α,β-unsaturated esters, a new way to construct 1,2-amino or 1,3-amino alcohol moieties in an acyclic system, is described. Very concise synthesis of d-vancosamine and 3-epi-d-vancosamine derivatives was also achieved utilizing this methodology.