- Asymmetric total synthesis of sperabillins B and D via lithium amide conjugate addition
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Diastereoselective conjugate addition of homochiral lithium (R)-N-allyl-N-α-methylbenzylamide to methyl (2E,5E)-hepatadienoate, followed by protecting group manipulation and subsequent iodocyclocarbamation allows a concise route to the core fragment, methyl (3R,5R,6R)-3,6-diamino-5- hydroxyheptanoate, of sperabillins B and D. Differentiation between the C-3 and C-6 primary amino groups of this core amino acid was readily achieved by treatment with acetone, giving the 5,6-isopropylidene and C-3-imine protected diamine, with subsequent regioselective acylation of the C-6-nitrogen facilitating the total synthesis of sperabillin D in 10.8% overall yield, and the first asymmetric synthesis of sperabillin B in 5.8% overall yield.
- Davies, Stephen G.,Haggitt, Jane R.,Ichihara, Osamu,Kelly, Richard J.,Leech, Michael A.,Mortimer, Anne J. Price,Roberts, Paul M.,Smith, Andrew D.
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p. 2630 - 2649
(2007/10/03)
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- Asymmetric synthesis of a highly functionalized β-amino acid: The key amino acid of sperabillins B and D
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The asymmetric synthesis of the highly functionalized (3R,5R,6R)-3,6-diamino-5-hydroxyheptanoic acid, the key amino acid fragment of sperabillins B and D, was achieved by an asymmetric Michael addition of lithium (R)-(α-methylbenzyl)allylamide 10 to (E,E)-2,5-heptadienoate establishing the C-3 stereogenic centre, the information from which was propagated to the C-5 and C-6 centres by a highly stereoselective iodocyclocarbamation reaction.
- Davies, Stephen G.,Ichihara, Osamu
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p. 9313 - 9316
(2007/10/03)
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