Cyclopropanation of alkynols with the CH2I2-R3Al system
作者:I. R. Ramazanov、A. V. Yaroslavova、U. M. Dzhemilev、O. M. Nefedov
DOI:10.1007/s11172-011-0051-9
日期:2011.2
Acetylenic alcohols bearing two or three methylene groups between the triple bond and hydroxy group react with CH2I2 in the presence of trialkylalanes to give 1,1,2-tri- and 1,1,2,2-tetrasubstituted cyclopropanes.
Elucidation of the stereostructure of the annonaceous acetogenin (+)-montecristin through total synthesis
作者:Christian Harcken、Reinhard Brückner
DOI:10.1039/b002905j
日期:——
Total syntheses of ent-5-epi-montecristin (1a) and of (−)-montecristin (1b) were accomplished. The stereocenters of compounds 1a and 1b were established by asymmetric dihydroxylations of the trans-configurated β,γ-unsaturated esters 6 ( → 4, up to 80% ee; Scheme 3; improved procedure with up to 94% ee: Scheme 7) and 56 ( → 55, 97% ee: Scheme 9) while the stereogenic CC bonds stem from the carbocuprations
Abstractn‐Alkyn‐1‐ols show fragmentation patterns which are influenced by the length of the chain and by the relative positions of the hydroxyl group and triple bond, and which allow a localization of the site of unsaturation.
Metal/ammonia reduction of ethers of 3-decyn-1-ol: effects of structure and conditions on cleavage and rearrangement
作者:Robert E. Doolittle、Delrea G. Patrick、Robert H. Heath
DOI:10.1021/jo00071a014
日期:1993.9
Reduction of the THP, ethyl, tert-butyl and tert-butyldimethylsilyl (TBDMS) ethers of 3-decyn-1-ol with sodium in ammonia/THF results in extensive hydrogenolysis of the carbon-oxygen bond and concomitant bond migration, producing a mixture of 2- and 3-decenes and a very low yield of the desired (E)-homoallylic ether. Reduction in the presence of 2-methyl-2-propanol led to excellent yields of the desired (E)-3-decenol ethers. The 4- and 5-decyn-1-ol ethers were reduced normally to the (E)-decen-1-ol ethers except in the case of the TBDMS ethers which were cleaved to the (E)-alcohols under some of the reaction conditions.
Synthesis of (4R,12S,15S,16S,19R,20R,34S)-Muricatetrocin and (4R,12R,15S,16S,19R,20R,34S)-Muricatetrocin, Two Potent Inhibitors of Mitochondrial Complex I