Radical cyclisations of methylenecyclopropyl azetidinones-synthesis of novel tricyclic ?-lactams
Radical cyclisations of methylenecyclopropyl azetidinones-synthesis of novel tricyclic ?-lactams
Addition of lithium bis(methylenecyclopropyl)cuprates to acetoxy azetidinones gives methylenecyclopropyl azetidinones, which can be converted to various radical cyclisation precursors. Attempted 4-exo cyclisation of 3 led only to reduced product, while cyclisation of 5, using CuCl/bipy, gave a carbacephem, via a 5-exo cyclisation, but in low yield. Cyclisation of 6 and 7, however, gave novel tricyclic ?-lactams, as the result of 7-endo cyclisation, in good yield, and a cyclisation of bromide 23 led to the tricyclic ?-lactam 24, via a radical cascade sequence.
methylenecyclopropane, cuprate, radical cyclisation, ?-lactam
cyclizations, derivatives, annelation, glycine
10347-10351
Penfold, D. J.
edea1171-3ca7-44b7-85b0-3029854b1e3f
Pike, K.
e9139c3d-9aa1-4ae0-bd87-04503ad97c50
Genge, A.
ee843380-cca3-4a4c-8c6f-ced5b10e399c
Anson, M.
8e68812b-cf53-4429-9b15-a93b510e4946
Kitteringham, J.
8710bb02-37f2-4e25-98f8-06a2389e60f5
Kilburn, J. D.
c02957da-baca-4138-961a-a85170d11dd8
23 December 2000
Penfold, D. J.
edea1171-3ca7-44b7-85b0-3029854b1e3f
Pike, K.
e9139c3d-9aa1-4ae0-bd87-04503ad97c50
Genge, A.
ee843380-cca3-4a4c-8c6f-ced5b10e399c
Anson, M.
8e68812b-cf53-4429-9b15-a93b510e4946
Kitteringham, J.
8710bb02-37f2-4e25-98f8-06a2389e60f5
Kilburn, J. D.
c02957da-baca-4138-961a-a85170d11dd8
Penfold, D. J., Pike, K., Genge, A., Anson, M., Kitteringham, J. and Kilburn, J. D.
(2000)
Radical cyclisations of methylenecyclopropyl azetidinones-synthesis of novel tricyclic ?-lactams.
Tetrahedron Letters, 41 (52), .
(doi:10.1016/S0040-4039(00)01860-8).
Abstract
Addition of lithium bis(methylenecyclopropyl)cuprates to acetoxy azetidinones gives methylenecyclopropyl azetidinones, which can be converted to various radical cyclisation precursors. Attempted 4-exo cyclisation of 3 led only to reduced product, while cyclisation of 5, using CuCl/bipy, gave a carbacephem, via a 5-exo cyclisation, but in low yield. Cyclisation of 6 and 7, however, gave novel tricyclic ?-lactams, as the result of 7-endo cyclisation, in good yield, and a cyclisation of bromide 23 led to the tricyclic ?-lactam 24, via a radical cascade sequence.
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Published date: 23 December 2000
Keywords:
methylenecyclopropane, cuprate, radical cyclisation, ?-lactam
cyclizations, derivatives, annelation, glycine
Identifiers
Local EPrints ID: 18931
URI: http://eprints.soton.ac.uk/id/eprint/18931
ISSN: 0040-4039
PURE UUID: ba40f550-5c23-4df6-b950-a2c56d597501
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Date deposited: 15 Dec 2005
Last modified: 15 Mar 2024 06:09
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Contributors
Author:
D. J. Penfold
Author:
K. Pike
Author:
A. Genge
Author:
M. Anson
Author:
J. Kitteringham
Author:
J. D. Kilburn
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