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Synthesis and reactions of unsaturated 14-membered lactones

University of British Columbia

Via a lactonization of the open chain hydroxy acid, the 14-membered unsaturated lactones 14 and 15 were synthesised. Treatment of these two lactones with borane dimethylsulphide, disiamyl borane and 9BBN led to formationof hydroxy lactones 30, 31, 32 and 33. The structures of 31 and 32 were determined by comparison with known compounds whereas structures 30 and 33 were deduced by considering the transition structures of the hydroboration reaction. Although both the regio and the stereoselectivity of the reactions were poor the π-face selectivity was high. Product distributions were estimated by the conformational control induced by the ring, using Houk's parameters for the hydroboration transition structures, in an MM2 force field, to calculate their relative strain energies. [ formulas omitted]

Text

2010-11-18

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http://hdl.handle.net/2429/30016

Chemistry

University of British Columbia

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