Zobrazeno 1 - 10
of 119
pro vyhledávání: '"W. Nico Speckamp"'
Publikováno v:
Recueil des Travaux Chimiques des Pays-Bas. 105:299-306
Alkylation of the lithium enolate, derived from 5-ethoxy-2-pyrrolidone 1 (Scheme 1), using alkyl halides containing either the vinylsilane or 2-propynylsilane moiety, provides substrates 3 for cyclization studies passing through N-acyliminium interme
Autor:
Urszula Grabowska, Henk Hiemstra, Floris P. J. T. Rutjes, W. Nico Speckamp, M. J. Moolenaar, Willem F. J. Karstens
Publikováno v:
Tetrahedron Letters, 40, 8629-8632. Elsevier
A formal total synthesis of natural (−)-epibatidine has been developed. Key steps in the synthesis are a copper(I)-mediated coupling of an (S)-pyroglutamic acid-derived organozinc reagent with 1-iodo-3-trimethylsilyl-1-propyne and an N-acyl- or N-s
Publikováno v:
European Journal of Organic Chemistry. 1998:1729-1737
Publikováno v:
Tetrahedron Letters. 38:155-158
The synthesis of a number of aza-analogues of (nor)tropanes is described. Key features of the synthesis include the efficient preparation of an enantiopure 5-substituted 3-pyrazolidinone and stereoselective cyclization of an N-acylhydrazonium ion int
Publikováno v:
Tetrahedron Letters. 38:159-162
An enantiopure aza-analogue of pseudo-cocaine was synthesized starting from a 5-substituted 3-pyrazolidinone by using an N-acylhydrazonium ion cyclization with a dioxenone nucleophile as the key step.
Publikováno v:
Journal of Photochemistry and Photobiology B: Biology. 36:139-142
In this article we report studies on the stability of Photofrin-II and Photosan-3 by inducing porphyrin disaggregation and monitoring changes in the UV/Vis absorption and fluorescence spectra. It was observed that the aggregates in Photosan-3 are mor
Publikováno v:
Tetrahedron, 52, 2603-2628. Elsevier
Highly stereoselective N -acyliminium ion coupling reactions of β-ketoester derived silyl enol ethers with enantiopure lactams derived from ( S )-malic acid are reported. This reaction type is applied in the synthesis of the enantiopure C-2 substitu
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a2a3b51b8a537e63703eb02bb32e08f1
https://dare.uva.nl/personal/pure/en/publications/studies-towards-the-synthesis-of-ptilomycalin-a-stereoselective-nacyliminium-ion-coupling-reactions-to-enantiopure-c2-substituted-lactams(fa02714d-4917-4308-9b03-211e539c3e13).html
https://dare.uva.nl/personal/pure/en/publications/studies-towards-the-synthesis-of-ptilomycalin-a-stereoselective-nacyliminium-ion-coupling-reactions-to-enantiopure-c2-substituted-lactams(fa02714d-4917-4308-9b03-211e539c3e13).html
Autor:
Henk Hiemstra, W. Nico Speckamp, Piet W. N. M. van Leeuwen, John W. Geus, Rolf A. T. M. van Benthem
Publikováno v:
Angewandte Chemie. 107:500-503
Publikováno v:
Tetrahedron. 50:8853-8862
An efficient Cu(bpy)Cl-catalysed N-acyliminium ion cyclisation to N-protected 3-azabicyclo[3.3.1]non-6-ene is reported. This compound has been demonstrated to be a valuable intermediate in the synthesis of 2,4-disubstituted 1-aza-adamantanes, and led
Publikováno v:
Tetrahedron: Asymmetry. 4:1941-1948
Conjugate addition reactions of amines and thiols to enantiopure ( R )-1-acetyl-5-isopropoxy-3-pyrrolin-2-one are shown to proceed with high stereoselectivity. The benzylamine and the benzyl mercaptan adducts were N -deacylated and then treated with