Coupling of AlkynylTMS Derivatives with Vinylic Iodides. An Efficient Route to 1,3-Enynes and Dienes
摘要:
[GRAPHICS]CuCl-promoted coupling of alkynylTMS derivatives with vinyl iodides leads to 1,3-enynes in high yield. Enynes prepared! from homopropargylic alcohols undergo intramolecular hydrosilylation and subsequent silyl cleavage with TBAF to afford 1,3-dienes.
Cyclopropane Compatibility with Oxidative Carbocation Formation: Total Synthesis of Clavosolide A
摘要:
Cyclopropane-substituted allylic ethers react with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone to form oxocarbenium ions with no competitive ring cleavage. This reaction can be used for the preparation of cyclopropane-substituted tetrahydropyrans. The protocol was used as a key step in the total synthesis of the sponge-derived macrolide clavosolide A.
A Pentenyl Dianion-Based Strategy for Convergent Synthesis of Ene-1,5-diols
作者:Adilah B. Bahadoor、Alec Flyer、Glenn C. Micalizio
DOI:10.1021/ja050039+
日期:2005.3.1
A convergent two-step process is described for the synthesis of ene-1,5-diols that provides for union of two carbonyl electrophiles via a formal pentenyl dianion equivalent.
The C13−C18 fragment 3 of the novel antibioticbranimycin was prepared along two highly stereocontrolled routes. The first one uses a standard Roush crotylation protocol, whereas the second one proceeds via an allenyl silane propargylation with unexpected stereochemical consequences, which are discussed in detail.
Total Synthesis of Iejimalide B. An Application of the Shiina Macrolactonization
作者:Dirk Schweitzer、John J. Kane、Daniel Strand、Peter McHenry、Martin Tenniswood、Paul Helquist
DOI:10.1021/ol702129w
日期:2007.10.1
The potent anticancer compound iejimalideB (1) was prepared by a totalsynthesis through a strategy that features Julia olefinations, Wittig olefinations, a Carreira enantioselective alkynylation, a Heck reaction, a Marshall propargylation reaction, a Stille coupling, and a Shiina macrolactonization.
Lipase-Mediated Resolution of 4-TMS-3-butyn-2-ol and Use of the Mesylate Derivatives as a Precursor to a Highly Stereoselective Chiral Allenylindium Reagent
作者:James A. Marshall、Harry R. Chobanian、Mathew M. Yanik
DOI:10.1021/ol016605x
日期:2001.10.1
[GRAPHICS]An improved procedure for the resolution of 4-trimethylsilyl-3-butyn-2-ol has been developed. The mesylate derivatives of the resolved alcohols have been found to undergo highly enantio-, regio-, and diastereoselective additions to aldehydes, leading to homopropargylic alcohol adducts.
Synthesis of the C6−C21 Segment of Amphidinolide E
作者:James A. Marshall、Gregory Schaaf、Andrew Nolting
DOI:10.1021/ol0523493
日期:2005.11.1
A convergent approach to a C6-C21 segment of the polyketide amphidinolide E has been developed through combination of three subunits by allenylindium bromide-aldehyde addition and Suzuki sp(2-)sp(3) coupling.