Stereodivergent Synthesis of Enantioenriched 4-Hydroxy-2-cyclopentenones
摘要:
Protected 4-hydroxycyclopentenones (4-HCPs) constitute an important class of intermediates in chemical synthesis. A route to this class of compound has been developed. Key steps include Noyori reduction (which establishes the stereochemistry of the product), ring-closing metathesis, and simple functional group conversions to provide a set of substituted 4-HCPs in either enantiomeric form.
Stereodivergent Synthesis of Enantioenriched 4-Hydroxy-2-cyclopentenones
摘要:
Protected 4-hydroxycyclopentenones (4-HCPs) constitute an important class of intermediates in chemical synthesis. A route to this class of compound has been developed. Key steps include Noyori reduction (which establishes the stereochemistry of the product), ring-closing metathesis, and simple functional group conversions to provide a set of substituted 4-HCPs in either enantiomeric form.
<i>P</i>-Stereogenic Bicyclo[4.3.1]phosphite Boranes: Synthesis and Utility of Tunable <i>P</i>-Tether Systems for the Desymmetrization of <i>C</i><sub>2</sub>-Symmetric 1,3-<i>anti</i>-Diols
作者:Jana L. Markley、Paul R. Hanson
DOI:10.1021/acs.orglett.7b00851
日期:2017.5.19
1]phosphite borane tether systems for the desymmetrization of C2-symmetric dienediols is reported. This report highlights preliminary studies including tether installation and removal as well as chemoselective functionalization of the exocyclic olefin via diimide reduction or cross-metathesis. Most notably, a divergent oxidation strategy allows for the transformation of the bicyclic phosphite borane complexes
Synthesis of the Bryostatin 1 Northern Hemisphere (C1−C16) via Desymmetrization by Ketalization/Ring-Closing Metathesis
作者:Eric A. Voight、Hassan Seradj、Paul A. Roethle、Steven D. Burke
DOI:10.1021/ol0483044
日期:2004.10.1
[reaction: see text] Synthesis of the northern hemisphere (C1-C16) of bryostatin 1, a potent anticancer agent, has been accomplished in 14 steps and 11% overall yield via desymmetrization by ketalization/ring-closing metathesis. A 2,9-dioxabicyclo[3.3.1]nonane template facilitated stereoselective A-ring functionalization, while an efficient hetero-Diels-Alder reaction was used to elaborate the B-ring
Stereoselective Total Synthesis of (−)-Kumausallene
作者:Jenny B. Werness、Weiping Tang
DOI:10.1021/ol201477u
日期:2011.7.15
A stereoselective total synthesis of (-)-kumausallene was completed in 12 steps from acetylacetone. The hidden symmetry of (-)-kumausallene was recognized, and its skeleton was constructed efficiently from a C(2)-symmetric diol by a palladium-catalyzed cascade reaction. High diastereoselectivity was observed for the DMF-promoted biomimetic 1,4-bromocyclization of a conjugated enyne.
A Novel Route to the F-Ring of Halichondrin B. Diastereoselection in Pd(0)-Mediated <i>meso</i> and <i>C</i><sub>2</sub> Diol Desymmetrization
作者:Lei Jiang、Steven D. Burke
DOI:10.1021/ol026504e
日期:2002.10.1
[GRAPHICS]Both sigma and C-2 symmetric diol diacetates were synthesized via two-directional chain elongation. A palladium-mediated, ligand-controlled C-2 diol desymmetrization provided the desired tetrahydrofuran with the correct relative and absolute stereochemistries. Simple functional group manipulation led to the desired F-ring of halichondrin B. Desymmetrization of the meso substrate enantioselectively provided the diastereomer, leading to a refinement of our understanding of the transition state model.
Total Synthesis of Dolabelide C: A Phosphate-Mediated Approach
作者:Paul R. Hanson、Rambabu Chegondi、John Nguyen、Christopher D. Thomas、Joshua D. Waetzig、Alan Whitehead
DOI:10.1021/jo2003506
日期:2011.6.3
The first synthesis of dolabelide C (1), a cytotoxic marine macrolide, is reported utilizing a phosphate tether-mediated approach. Bicyclic phosphates (S,S,S-p)-5 and (R,R,R-p)-5 serve as the central building blocks for the construction of two major 1,3-anti-diol subunits in 1 through selective cleavage pathways, regioselective olefin reduction, and cross-metathesis. Overall, phosphate-mediated processes provided copious amounts of both major subunits allowing for a detailed RCM macrocyclization study to the 24-membered macrolactone 1.