Selective Formation of a Trisubstituted Alkene Motif bytrans-Hydrostannation/Stille Coupling: Application to the Total Synthesis and Late-Stage Modification of 5,6-Dihydrocineromycin B

2015 ◽  
Vol 127 (21) ◽  
pp. 6339-6343 ◽  
Author(s):  
Stephan M. Rummelt ◽  
Johannes Preindl ◽  
Heiko Sommer ◽  
Alois Fürstner
Keyword(s):  
Total Synthesis ◽  
Late Stage ◽  
Stille Coupling ◽  
Selective Formation

Total Synthesis of Lamellarins U and A3 by Interrupting Halogen Dance

Synthesis ◽  
2022 ◽  
Author(s):  
Yuya Okui ◽  
Yuto Yasuda ◽  
Atsunori Mori ◽  
Kentaro Okano
Keyword(s):  
Total Synthesis ◽  
Late Stage ◽  
Pyrrole Ring ◽  
Stille Coupling ◽  
Aryl Group ◽  
Negishi Coupling ◽  
Halogen Dance Reaction ◽  
Magnesium Exchange

A total synthesis of lamellarins U and A3 is described. The synthesis features interruption of a halogen dance reaction of a metalated α,β-dibromopyrrole. The pyrrolylmagnesium reagent, generated by deprotonative metalation using (TMP)MgCl·LiCl (TMP: 2,2,6,6-tetramethylpiperidide) as base, was transmetalated to the corresponding organozinc species without causing the halogen dance reaction, which underwent a Negishi coupling to incorporate an aryl group onto the pyrrole ring. The arylated α,β-dibromopyrrole was then converted into lamellarins U and A3 through an α-selective halogen–magnesium exchange followed by carboxylation and subsequent palladium-mediated cyclization. The late-stage introduction of another aryl group was performed using a Kosugi–Migita–Stille coupling to provide lamellarins U and A3.

Convergent Total Synthesis of Principinol D, a Rearranged Kaurane Diterpenoid

2019 ◽  
Author(s):  
Timothy Newhouse ◽  
Aneta Turlik ◽  
Yifeng Chen ◽  
Anthony Scruse
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Late Stage ◽  
Membered Ring ◽  
Entry Point ◽  
Ketone Reduction ◽  
Coupling Approach

<div> <p>The total synthesis of principinol D, a rearranged kaurane diterpenoid, is reported. This grayanane natural product is constructed via a convergent fragment coupling approach, wherein the central 7-membered ring is synthesized at a late stage. The bicyclo[3.2.1]octane fragment is accessed by a Ni-catalyzed α-vinylation reaction. Strategic reductions include a diastereoselective SmI<sub>2</sub>-mediated ketone reduction with PhSH and a new protocol for selective ester reduction in the presence of ketones. The convergent strategy reported herein may be an entry point to the larger class of kaurane diterpenoids.</p> </div>

The Total Synthesis of Rhabdastrellic Acid A

2018 ◽  
Author(s):  
Yaroslav Boyko ◽  
Christopher Huck ◽  
David Sarlah
Keyword(s):  
Total Synthesis ◽  
Late Stage ◽  
Cross Coupling ◽  
Side Chains ◽  
General Strategy ◽  
Modular Approach ◽  
Linear Sequence ◽  
Generating Sequence ◽  
First Time

<div>The first total synthesis of rhabdastrellic acid A, a highly cytotoxic isomalabaricane triterpenoid, has been accomplished in a linear sequence of 14 steps from commercial geranylacetone. The prominently strained <i>trans-syn-trans</i>-perhydrobenz[<i>e</i>]indene core characteristic of the isomalabaricanes is efficiently accessed in a selective manner for the first time through a rapid, complexity-generating sequence incorporating a reductive radical polyene cyclization, an unprecedented oxidative Rautenstrauch cycloisomerization, and umpolung 𝛼-substitution of a <i>p</i>-toluenesulfonylhydrazone with in situ reductive transposition. A late-stage cross-coupling in concert with a modular approach to polyunsaturated side chains renders this a general strategy for the synthesis of numerous family members of these synthetically challenging and hitherto inaccessible marine triterpenoids.</div>

scholarly journals Back Cover: Total Synthesis of (−)‐Salinosporamide A via a Late Stage C−H Insertion (Angew. Chem. Int. Ed. 30/2019)

2019 ◽  
Vol 58 (30) ◽  
pp. 10376-10376
Author(s):  
Hadi Gholami ◽  
Aman Kulshrestha ◽  
Olivia K. Favor ◽  
Richard J. Staples ◽  
Babak Borhan
Keyword(s):  
Total Synthesis ◽  
Late Stage ◽  
Back Cover ◽  
Salinosporamide A

Enantioselective Total Synthesis of (+)‐Flavisiamine F via Late‐Stage Visible‐Light‐Induced Photochemical Cyclization

2019 ◽  
Vol 131 (16) ◽  
pp. 5497-5500 ◽  
Author(s):  
Xiaogang Tong ◽  
Bingfei Shi ◽  
Kangjiang Liang ◽  
Qian Liu ◽  
Chengfeng Xia
Keyword(s):  
Total Synthesis ◽  
Visible Light ◽  
Late Stage ◽  
Enantioselective Total Synthesis

Asymmetric total synthesis of cryptoconcatone I

2019 ◽  
Vol 17 (14) ◽  
pp. 3552-3566 ◽  
Author(s):  
Ranjan Kumar Acharyya ◽  
Pratik Pal ◽  
Shrestha Chatterjee ◽  
Samik Nanda
Keyword(s):  
Total Synthesis ◽  
Late Stage ◽  
Ring Opening ◽  
Epoxide Ring ◽  
Asymmetric Total Synthesis ◽  
Epoxide Ring Opening ◽  
Cascade Cyclization ◽  
Naturally Occurring

An efficient asymmetric total synthesis of naturally occurring γ-Z-butenolide cryptoconcatone I was achieved by employing substrate-directed reductive epoxide ring opening and late-stage “Pd–Cu” catalyzed cascade cyclization.

Total Synthesis of Stemoamide, 9a-epi-Stemoamide, and 9a,10-epi-Stemoamide: Divergent Stereochemistry of the Final Methylation Steps

Synlett ◽  
2020 ◽  
Vol 31 (16) ◽  
pp. 1581-1586
Author(s):  
Imre Pápai ◽  
Petri M. Pihko ◽  
Juha H. Siitonen ◽  
Dániel Csókás
Keyword(s):  
Total Synthesis ◽  
Late Stage ◽  
Total Syntheses ◽  
Forming Strategy ◽  
Kinetic Selectivity

Total syntheses of stemoamide, 9a-epi-stemoamide, and 9a,10-epi-stemoamide by a convergent A + B ring-forming strategy is reported. The synthesis required a diastereoselective late-stage methylation of the ABC stemoamide core that successfully enabled access to three of the four possible diastereomeric structures. For the natural stemoamide series, the diastereoselectivity can be rationalized both by kinetic and thermodynamic arguments, whereas for the natural 9a-epi-stemoamide series, the kinetic selectivity is explained by the prepyramidalization of the relevant enolate.

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