- Æ. Groot de (4)
- B.J.M. Jansen(older publications) (2)
- B.J.M. Jansen (2)
- L.H.D. Jenniskens (2)
- F. Macaev (1)
- T.M. Meulemans (2)
- F.C.E. Sarabèr (2)
- H.J. Swarts (1)
- A.A. Verstegen-Haaksma (1)
- E. Zhernosek (1)
Domino Mukaiyama-Michael reactions in the synthesis of polycyclic systems
Sarabèr, F.C.E. ; Dratch, S. ; Bosselaar, G. ; Jansen, B.J.M. ; Groot, Æ. de - \ 2006
Tetrahedron 62 (2006)8. - ISSN 0040-4020 - p. 1717 - 1725.
silyl enol ethers - catalyzed conjugate addition - vitamin-d-3 northern portion - ring closure reactions - one-pot - acyclic stereoselection - titanium tetrachloride - 2+2+2 construction - carbonyl-compounds - organic-synthesis
Good results were obtained in the Mukaiyama-Michael reaction of the silyl enol ether of cyclohexanone with 2-methyl-2cyclopentenone and carvone, with transfer of the silyl group to the receiving enone and with TrSbCl6 as catalyst. A second Mukaiyama-Michael reaction of this new silyl enol ether with methyl vinyl ketone and cyclization of the resulting adduct leads to tricyclic compounds in one-pot domino sequences. The scope and limitations of this domino reaction have been investigated.
A new approach toward the synthesis of C,D-cis coupled steroid and C,D-cis coupled D-homosteroid skeletons
Dratch, S. ; Charnikhova, T. ; Sarabèr, F.C.E. ; Jansen, B.J.M. ; Groot, Æ. de - \ 2003
Tetrahedron 59 (2003)24. - ISSN 0040-4020 - p. 4287 - 4295.
A short and efficient procedure has been developed for the synthesis of C,D-cis coupled steroid and D-homo steroid skeletons. A Mukaiyama reaction with transfer of the silyl group of the starting silyl enol ether to the enol of the adduct followed by addition of vinyl magnesium bromide to the unprotected carbonyl group leads to adducts which can be cyclized with ZnBr2. The synthesis of functionalized steroid skeletons in overall yields of about 50% in four steps can be achieved in this way. (C) 2003 Elsevier Science Ltd. All rights reserved.
|S-(+)- and R-(-)Carvone as starting material in the Enantiose-lective synthesis of natural products.
Groot, Æ. de; Jansen, B.J.M. ; Meulemans, T.M. ; Jenniskens, L.H.D. ; Dratch, S.V. ; Baranovsky, A. ; Zhernosek, E. ; Macaev, F. - \ 1998
In: International Conference on Natural products and Physiologically Active Substances, Novosibirsk, Russia
|R-(-)- and S-(+)-carvone as starting material in the enantioselective synthesis of natural products.
Groot, Æ. de; Verstegen-Haaksma, A.A. ; Swarts, H.J. ; Jansen, B.J.M. ; Meulemans, T.M. ; Jenniskens, L.H.D. ; Dratch, S.V. ; Baranovsky, A. - \ 1997
In: XVII Conference on Isoprenoids, Krakow, Poland - p. 4 - 4.