Baggiolini, Enrico G. published the artcileStereocontrolled total synthesis of 1α,25-dihydroxycholecalciferol and 1α,25-dihydroxyergocalciferol, Category: tetrahydropyran, the publication is Journal of Organic Chemistry (1986), 51(16), 3098-108, database is CAplus.
1α,25-Dihydroxycholecalciferol and 1α,25-dihydroxyergocalciferol, the hormonally active forms of vitamin D3 and vitamin D2, were prepd by Horner-Wittig reaction of the phosphine oxide I [R = CH2P(O)Ph2] (II) with ketones III and IV, resp. The synthon III was obtained via stereospecific opening of epoxide V with NaOAc in AcOH followed by oxidative degradation of the isopropenyl side chain and dehydration of the intermediate VI. Photoisomerization of the resulting (E)-I (R = CO2Et) gave I (R = CO2Et), which was converted to II. III was obtained from the known intermediate VII. The introduction of the 25-hydroxy side chain was achieved by reaction of the lithium derivative of HCCCMe2OR1 (R1 = tetrahydropyranyl) with the tosylate of VII; subsequent hydrogenation, deblocking, and oxidation reactions gaave III. IV was prepared by a stereocontrolled route that involves as the key step the [3 + 2] dipolar cycloaddition of nitrone VII with Me2C:CHCO2Me to give a 1:1 mixture of isoxazolidines IX. Stereochem. control was achieved by taking advantage of the thermal reversibility of the cycloaddition, which allows the reequilibration of undersired IX. (23S, 24S)-IX was readily transformed to amine X by reduction, followed by elimination of the nitrogen function, and finally oxidation to IV.
Journal of Organic Chemistry published new progress about 27943-46-0. 27943-46-0 belongs to tetrahydropyran, auxiliary class Tetrahydropyran,Alkynyl,Ether, name is 2-((2-Methylbut-3-yn-2-yl)oxy)tetrahydro-2H-pyran, and the molecular formula is C10H16O2, Category: tetrahydropyran.
Referemce:
https://en.wikipedia.org/wiki/Tetrahydropyran,
Tetrahydropyran – an overview | ScienceDirect Topics