112763-33-4Relevant academic research and scientific papers
Electrophilic Cyclization of 1,6-Dienes Containing an Allylsilane Moiety - Enantioselective Synthesis of cis- and trans-γ-Irone
Beszant, Stephen,Giannini, Elios,Zanoni, Giuseppe,Vidari, Giovanni
, p. 3958 - 3968 (2003)
In this paper, we report the first examples of Lewis acid and mercuric trifluoroacetate promoted cyclizations of 1,6-dienes containing an allylsilane moiety. Mercuric trifluoroacetate has been proved to be the reagent of choice leading to methylenecyclohexane derivatives in good yields and with complete regioselectivity albeit with poor diastereoselectivity. Using this methodology a stereodivergent synthesis of enantiomerically pure (-)-(2S,6R)-cis-γ -irone and (-)-(2S,6S)-trans-γ-irone, two precious aroma constituents, has been accomplished. This represents an innovative approach with respect to previous syntheses of γ-irones. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
Studies for the enantiocontrolled preparation of substituted tetrahydropyrans: Applications for the synthesis of leucascandrolide A macrolactone
Williams, David R.,Plummer, Scott V.,Patnaik, Samarjit
, p. 5083 - 5097 (2011/07/31)
Strategies for the stereocontrolled preparations of 2,6-cis- and 2,6-trans-substituted tetrahydropyrans have been devised. These studies have explored methodology for asymmetric induction in SE′ reactions using chiral 1,3,2-diazaborolidine controllers. Reactions with aldehydes at -78°C yield nonracemic 1,5-diols for chemoselective internal backside displacements. This concept is developed as a flexible and reliable strategy in studies toward leucascandrolide A macrolactone 2 via the sequential applications of SE′ reactions leading to the C1-C9 aldehyde 14, and the bis-tetrahydropyran 59, respectively.
Total Synthesis of (-)-C34-Botryococcene, the Principal Triterpenoid Hydrocarbon of the Freshwater Alga Botryococcus braunii
White, James D.,Reddy, G. Nagabushana,Spessard, Gary O.
, p. 759 - 768 (2007/10/02)
The hydrocarbon (-)-C34-botryococcene 1 has been synthesized in enantiomerically pure form by coupling the alkylcopper species 41 to each terminus of diiodide 37.The former was prepared from (2S)-3-hydroxy-2-methylpropionate 2 which was first converted into the alcohol 7.Coupling of the dianion of 7, obtained by deprotonation with the Schlosser base, with tosyl ester 11 gave the alcohol 12 and thence iodide 39.The central segment 37 of the botryococcene chain was synthesized from (2R)-3-hydroxy-2-methylpropionate 15 and entailed a novel rearrangement of the derived αβ-unsatured MOM ester 23 to establish the quaternary allylic centre at C-13.The pair of stereoisomeric hydroxy esters 24 and 25 obtained from this rearrangement were independently advanced to stereochemical convergence at 29, which was subsequently transformed into diiodide 37.The route of synthesis confirms the previous assignment of absolute configuration made to botryococcene 1 at five of the six stereogenic centres, i.e. (3S,7S,10R,16S,20S).
