599165-21-6Relevant articles and documents
Facile construction of the 7,8-olefin linkage in vitamin D3: A practical synthesis benefiting the vitamin D3 analog study
Ono, Yoshiyuki,Kashiwagi, Hirotaka,Takahashi, Tadakatsu
, p. 1141 - 1146 (2006)
A facile procedure for construction of the 7,8-olefin linkage in vitamin D3 is described. Treatment of a mixture of A-ring phosphine oxide and CD-ring ketone in THF with lithium hexamethyldisilazide (LHMDS) at -20°C followed by gradual heating
New Convergent Synthesis of 1α,25-Dihydroxyvitamin D3 and Its Analogues by Suzuki-Miyaura Coupling between A-Ring and C,D-Ring Parts
Hanazawa, Takeshi,Koyama, Akiko,Nakata, Kunio,Okamoto, Sentaro,Sato, Fumie
, p. 9767 - 9772 (2007/10/03)
A new convergent method for the synthesis of 1α,25 -dihydroxyvitamin D3 and its analogues has been developed that involves efficient preparation of the A-ring part 1a, (Z)-(3S,5R)-1-bromom-ethylene-3,5-bis(tert-butyldimethylsilyloxy) -2-methylenecyclohexane, starting from epichlorohydrin (4) and its Suzuki-Miyaura coupling reaction with the C,D-ring part 12. Thus, (R)-4 was converted to (3S,5R)-5-(tert-butyldimethylsilyloxy)-8-(trimethylsilyl)-oct-l-en-7-yn-3-ol (3a) through a ten-step reaction sequence in 49% overall yield. Compound 3a thus obtained was treated with a Ti(O-i-Pr)4/2 i-PrMgCl reagent and then with NBS to afford (Z)-(1S,2S,5R)-2-bromomethyl-3-[bromo-(trimethylsilyl)methylene] -5-(tert-butyldimethylsilyloxy)cyclohexanol (10a) in 51% yield, from which la was obtained in 87% yield by sequential treatment with TBSCl/imidazole, DBU, and Cs2CO3. The resulting A-ring intermediate 1a was reacted with alkenylboronate 12 in the presence of a PdCl2(dppf) catalyst to furnish 1α,25 -dihydroxyvitamin D3 in 82% yield after protodesilylation. Similarly, all of the other three possible stereoisomers of A-ring parts 1b, 1c, and 1d were prepared, from which 1-epi-, 3-epi-, and 1,3-di-epi-1α,25-dihydroxyvitamin D3 were synthesized by coupling with 12 in excellent yield, respectively. Starting from 1a and 1c, des-C,D-1α,25-dihydroxyvitamin D3 analogues, retiferol 13 and its 3-epi derivative, were also prepared, respectively.
Stereoselective Total Synthesis of 1α,25-Dihydroxycholecalciferol
Baggiolini, Enrico G.,Iacobelli, Jerome A.,Hennessy, Bernard M.,Uskokovic, Milan R.
, p. 2945 - 2948 (2007/10/02)
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