TY - JOUR
T1 - Alkene protection against acid using a bromide substituent
T2 - Application in a total synthesis of (-)-6,7-dideoxysqualestatin H5
AU - Almohseni, Hasanain A.A.
AU - Al Mamari, Hamad H.
AU - Valade, Anne
AU - Sintim, Herman O.
AU - Hodgson, David M.
N1 - Funding Information:
We thank the Higher Committee for Education Development in Iraq, the Sultanate of Oman and the University of Oxford for studentship support (to H. A. A. A., H. H. A. M., and H. O. S., respectively), and the European Union for a Marie Curie Fellowship (MEIF-CT-2004-515366 to A. V.).
Publisher Copyright:
© 2018 The Royal Society of Chemistry.
PY - 2018
Y1 - 2018
N2 - The presence of a bromide substituent, instead of a hydrogen or methyl group, on a carbon-carbon double bond, protects the alkene from addition reactions when exposed to trifluoroacetic acid. This concept is used to circumvent concomitant loss of unsaturation in a late-stage acid-catalysed 6,8- to 2,8-dioxabicyclo[3.2.1]octane rearrangement towards (-)-6,7-dideoxysqualestatin H5. The inertness of the alkenyl bromide functionality is demonstrated through several synthetic transformations in the assembly of the rearrangement substrate. Completion of the natural product synthesis is facilitated by post-rearrangement removal of the bromide substituent through stereoselective C-C cross-coupling in the presence of ester and hydroxyl functionalities.
AB - The presence of a bromide substituent, instead of a hydrogen or methyl group, on a carbon-carbon double bond, protects the alkene from addition reactions when exposed to trifluoroacetic acid. This concept is used to circumvent concomitant loss of unsaturation in a late-stage acid-catalysed 6,8- to 2,8-dioxabicyclo[3.2.1]octane rearrangement towards (-)-6,7-dideoxysqualestatin H5. The inertness of the alkenyl bromide functionality is demonstrated through several synthetic transformations in the assembly of the rearrangement substrate. Completion of the natural product synthesis is facilitated by post-rearrangement removal of the bromide substituent through stereoselective C-C cross-coupling in the presence of ester and hydroxyl functionalities.
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U2 - 10.1039/c8cc02690d
DO - 10.1039/c8cc02690d
M3 - Article
C2 - 29741545
AN - SCOPUS:85047493501
SN - 1359-7345
VL - 54
SP - 5354
EP - 5356
JO - Chemical Communications
JF - Chemical Communications
IS - 42
ER -