- Synthetic studies on spiroketal natural products. IV. A stereoselective synthesis of (3S,5S,6R,9R,R(S))-3-benzyloxymethyl-9-hydroxymethyl-5-(p-tolyl)sulfin yl-1,7-dioxaspiro[5.5]undecane, a key intermediate for talaromycins
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A dioxaspiro compound (4), a common intermediate for the synthesis of talaromycin A (1) and (-)-talaromycin B (2), was synthesized by two routes utilizing two kinds of asymmetric recognition of prochiral 1,3-diols controlled by sulfinyl chirality, that is, firstly by acid promoted diastereoselective C-O bond fission of the bicyclic acetal (7) to give the dihydropyran derivative (6), which has an S-hydroxymethyl group at the C3-position (7 → 6), and secondly by diastereoselective intramolecular Michael addition of the diol (5), in which the three chiral centers at C5, C6, C9 were constructed in one step (5 → 4).
- Iwata,Maezaki,Hattori,Fujita,Moritani,Takemoto,Tanaka,Imanishi
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p. 339 - 345
(2007/10/02)
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- ASYMMETRIC FUNCTIONALIZATION AT A PROCHIRAL CARBON CENTER BY THE AID OF SULFINYL CHIRALITY: A SELECTIVE FORMATION OF 6-SUBSTITUTED (3R,SS)- AND (3S,SS)-3-HYDROXYMETHYL-3,4-DIHYDRO-5-(p-TOLYL)SULFINYL-2H-PYRANS
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A successful asymmetric functionalization of prochiral gem-bis(hydroxymethyl) groups has been achieved by the aid of a sulfinyl chirality.
- Iwata, Chuzo,Fujita, Masahiro,Moritani, Yasunori,Sugiyama, Kenji,Hattori, Kohji,Imanishi, Takeshi
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p. 3131 - 3134
(2007/10/02)
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