Silicon-initiated carbonylative carbotricyclization and [2+2+2+1] cycloaddition of enediynes catalyzed by rhodium complexes
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TLDR
These new processes provide innovative routes to functionalized polycyclic compounds that are useful for the syntheses of natural and unnatural products.Abstract:
The reaction of dodec-11-ene-1,6-diynes or their heteroatom congeners with a hydrosilane catalyzed by Rh(acac)(CO)2 at ambient temperature and pressure of CO gives the corresponding fused 5-7-5 tricyclic products, 5-oxo-1,3a,4,5,7,9-hexahydro-3H-cyclopenta[e]azulenes or their heteroatom congeners, in excellent yields through a unique silicon-initiated cascade carbonylative carbotricyclization (CO-SiCaT) process. It has also been found that the 5-7-5 fused tricyclic products can be obtained from the same type of enediynes and CO through a novel intramolecular [2+2+2+1] cycloaddition process. The characteristics of these two tricyclization processes and the fundamental differences in their reaction mechanisms are discussed. This novel higher-order cycloaddition reaction has also been successfully applied to the tricyclization of undeca-5,10-diyn-1-als, affording the corresponding 5-7-5 fused-ring products bearing a seven-membered lactone moiety. Related [2+2+2] tricyclizations of enediyne and diynal substrates are also discussed. These newly discovered reactions can construct multiple bonds all at once, converting linear starting materials to polycyclic compounds in a single step. Thus, these new processes provide innovative routes to functionalized polycyclic compounds that are useful for the syntheses of natural and unnatural products.read more
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Journal ArticleDOI
Intermolecular Rhodium-Catalyzed [3+2+2] Carbocyclization of Alkenylidenecyclopropanes with Activated Alkynes: Regio- and Diastereoselective Construction of cis-Fused Bicycloheptadienes
TL;DR: This study delineates some of the critical features for controlling regioselectivity in the carbocyclization of carbon- and heteroatom-tethered alkenylidenecyclopropanes with mono- and disubstituted alkynes and demonstrates that E-alkenes can be incorporated in a stereospecific manner to afford products with up to three new stereogenic centers.
Journal ArticleDOI
Allenes, versatile unsaturated motifs in transition-metal-catalysed [2+2+2] cycloaddition reactions
TL;DR: This tutorial review highlights the value that allenes have as reagents in [2+2-2] cycloaddition and their great versatility for the development of methods to generate complex architectures.
Journal ArticleDOI
Enantioselective Synthesis of Spirocyclic Benzopyranones by Rhodium‐Catalyzed Intermolecular [4+2] Annulation
Journal ArticleDOI
Rh(I)-Catalyzed Formal [5+1]/[2+2+1] Cycloaddition of 1-Yne-vinylcyclopropanes and Two CO Units: One-Step Construction of Multifunctional Angular Tricyclic 5/5/6 Compounds
TL;DR: A novel Rh(I)-catalyzed formal cycloaddition of 1-yne-vinylcyclopropanes and two CO units for the construction of multifunctional angular tricyclic 5/5/6 skeletons with one or two adjacent bridgehead quaternary all-carbon stereocenters in one step has been developed.
References
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Journal ArticleDOI
The behavior of 1,n-enynes in the presence of transition metals.
Journal ArticleDOI
Chelation or Non‐Chelation Control in Addition Reactions of Chiral α‐ and β‐ Alkoxy Carbonyl Compounds [New Synthetic Methods (44)]
TL;DR: In this article, two strategies have been developed: (1) Use of Lewisacidic reagents which form intermediate chelates, these being attacked stereoselectively from the less hindered side (chelation control); (2) use of reagents incapable of chelation, stereoselection attack being governed by electronic and/or steric factors (non-chelation Control).
Journal ArticleDOI
Unusual activity and selectivity in alkyne hydrosilylation with an iridium catalyst stabilized by an O-donor ligand
TL;DR: In this article, a catalytic alkyne hydrosilylation was found for iridium in the O-donor ligand environment of Grim's triso ligand.
Book
Organic Synthesis: Theory and Applications
TL;DR: The role of organic synthesis in the generation of molecular diversity was discussed in this paper. But this work focused on the synthesis of cyclobutanes, and not on higher terpenes.
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