- Towards synthesis of calysterols, marine sterols with cyclopropene moiety in the side chain: Synthesis of 26,27-Dinor-23H-isocalysterol
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26,27-Dinor-23H-isocalysterol 24 has been synthesized in 19% yield (6 steps) from ethyl 6β-methoxy-3α,5-cyclo-5α-pregnan-21-oate (18). For construction of the side chain, alkylation of lithium salt of ester 18 with 1-bromo-1,2-dimethyl-c-3-iodomethyl-c-2-(trimethylsilyl)cyclopropane 16 was used. It has been shown that reduction of the ester group in position 21 and rearrangement of the 3,5-cyclosteroid system are compatible with the sidechain functionalities. It has been found that methylation of 1,1-dibromo-2-(trimethylsilyl)cyclopropane is accompanied by an rearrangement involving 1,2-migration of the trimethylsilyl group.
- Kurek-Tyrlik, Alicja,Minksztym, Kazimierz,Wicha, Jerzy
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p. 1575 - 1588
(2007/10/03)
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- Synthesis of Four Stereoisomeric Tetrose Derivatives from Propargyl Alcohol. One-carbon Homologation of Vinylsilanes via α,β-Epoxy Silanes
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Silicon-mediated synthesis of stereomeric tetroses 1, 2, 3, and 4, from propargyl alcohol is described.An allylic alcohol bearing the trimethylsilyl group in the γ position, rac-9b, was subjected to the Sharpless kinetic resolution to give (2S)-9b and the
- Achmatowicz, Barbara,Raubo, Piotr,Wicho, Jerzy
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p. 6593 - 6598
(2007/10/02)
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