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Maurice Santelli - One of the best experts on this subject based on the ideXlab platform.
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Sakurai Reaction Addition of 1,8-Bis(trimethylsilyl)-2,6-octadiene to α,β-Enones. A One-Step Control of Four Stereogenic Carbon Centers
The Journal of Organic Chemistry, 1998Co-Authors: Hélène Pellissier, And Loïc Toupet, Maurice SantelliAbstract:The addition reaction of 1,8-bis(trimethylsilyl)-2,6-octadiene with open-chain conjugated enones in the presence of titanium tetrachloride affords 4,7-divinyldecane-1,10-diones with very high diastereoselectivity. In the case of benzalacetone (trans-4-phenyl-3-buten-2-one), the structure of the adduct (74% yield) was established as the Meso Isomer (4S*,5R*,8S*,9R*)-4,9-diphenyl-5,8-divinyldodecane-2,11-dione by a single-crystal X-ray analysis.
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Titanium Tetrachloride Mediated Addition of 1,8-Bis(trimethylsilyl)-2,6-octadiene to Aldehydes. A One-Step Control of Four Stereogenic Carbon Centers
The Journal of Organic Chemistry, 1994Co-Authors: Hélène Pellissier, Loïc Toupet, Maurice SantelliAbstract:The addition reaction of 1,8-bis(trimethylsilyl)-2,6-octadiene with aliphatic aldehydes in the presence of titanium tetrachloride affords 2,5-divinylhexane-1,6-diols with very high diastereoselectivity (up to 90%) and good yields (ca. 70-75%). In the case of benzaldehyde, the structure of the adduct was established as the Meso Isomer (1S * ,2R * ,5S * ,6R * )-1,6-diphenyl-2,5-divinyl-1,6-hexanediol by single-crystal X-ray analysis
Hélène Pellissier - One of the best experts on this subject based on the ideXlab platform.
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Sakurai Reaction Addition of 1,8-Bis(trimethylsilyl)-2,6-octadiene to α,β-Enones. A One-Step Control of Four Stereogenic Carbon Centers
The Journal of Organic Chemistry, 1998Co-Authors: Hélène Pellissier, And Loïc Toupet, Maurice SantelliAbstract:The addition reaction of 1,8-bis(trimethylsilyl)-2,6-octadiene with open-chain conjugated enones in the presence of titanium tetrachloride affords 4,7-divinyldecane-1,10-diones with very high diastereoselectivity. In the case of benzalacetone (trans-4-phenyl-3-buten-2-one), the structure of the adduct (74% yield) was established as the Meso Isomer (4S*,5R*,8S*,9R*)-4,9-diphenyl-5,8-divinyldodecane-2,11-dione by a single-crystal X-ray analysis.
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Titanium Tetrachloride Mediated Addition of 1,8-Bis(trimethylsilyl)-2,6-octadiene to Aldehydes. A One-Step Control of Four Stereogenic Carbon Centers
The Journal of Organic Chemistry, 1994Co-Authors: Hélène Pellissier, Loïc Toupet, Maurice SantelliAbstract:The addition reaction of 1,8-bis(trimethylsilyl)-2,6-octadiene with aliphatic aldehydes in the presence of titanium tetrachloride affords 2,5-divinylhexane-1,6-diols with very high diastereoselectivity (up to 90%) and good yields (ca. 70-75%). In the case of benzaldehyde, the structure of the adduct was established as the Meso Isomer (1S * ,2R * ,5S * ,6R * )-1,6-diphenyl-2,5-divinyl-1,6-hexanediol by single-crystal X-ray analysis
Hairong Guan - One of the best experts on this subject based on the ideXlab platform.
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Configurational Stability and Stereochemistry of P-Stereogenic Nickel POCOP-Pincer Complexes
Organometallics, 2015Co-Authors: Anubendu Adhikary, Jeanette A. Krause, Hairong GuanAbstract:The P-stereogenic nickel complex {2,6-[(t-Bu)(Ph)PO]2C6H3}NiCl (2) has been synthesized via cyclometalation of the POCOP-pincer ligand 1,3-[(t-Bu)(Ph)PO]2C6H4 (1) with NiCl2. The initially isolated 2 consists of a 1:1 mixture of racemic and Meso Isomers that are separable through repeated crystallization and is configurationally stable even at 110 °C. Upon mixing with t-BuOK, the Meso Isomer (2-Meso) displays a higher ligand substitution rate than the racemic Isomer (2-rac), likely because its nickel center is sterically more accessible. Complex 2, as either pure 2-rac or a 2-rac/2-Meso mixture, can be converted to the nickel triflate complex {2,6-[(t-Bu)(Ph)PO]2C6H3}NiOTf (3) or the nickel formate complex {2,6-[(t-Bu)(Ph)PO]2C6H3}NiOCHO (7) without epimerization at the phosphorus centers. Under a dynamic vacuum at 90 °C, decarboxylation of 7-Meso is faster than that of 7-rac, suggesting that in the transition state the formato hydrogen approaches the nickel center from the axial site rather than the equa...
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Configurational Stability and Stereochemistry of P‑Stereogenic Nickel POCOP-Pincer Complexes
2015Co-Authors: Anubendu Adhikary, Jeanette A. Krause, Hairong GuanAbstract:The P-stereogenic nickel complex {2,6-[(t-Bu)(Ph)PO]2C6H3}NiCl (2) has been synthesized via cyclometalation of the POCOP-pincer ligand 1,3-[(t-Bu)(Ph)PO]2C6H4 (1) with NiCl2. The initially isolated 2 consists of a 1:1 mixture of racemic and Meso Isomers that are separable through repeated crystallization and is configurationally stable even at 110 °C. Upon mixing with t-BuOK, the Meso Isomer (2-Meso) displays a higher ligand substitution rate than the racemic Isomer (2-rac), likely because its nickel center is sterically more accessible. Complex 2, as either pure 2-rac or a 2-rac/2-Meso mixture, can be converted to the nickel triflate complex {2,6-[(t-Bu)(Ph)PO]2C6H3}NiOTf (3) or the nickel formate complex {2,6-[(t-Bu)(Ph)PO]2C6H3}NiOCHO (7) without epimerization at the phosphorus centers. Under a dynamic vacuum at 90 °C, decarboxylation of 7-Meso is faster than that of 7-rac, suggesting that in the transition state the formato hydrogen approaches the nickel center from the axial site rather than the equatorial site. The structure of 2-rac has been studied by X-ray crystallography
Kenneth C. Cassidy - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of a new ketone and alcohol with C2 symmetry; (S,S,S,S) tricyclo[6.3.0.03,7]undecan-2-onela and (S,S,S,S) tricyclo[6.3.0.03,7]undecan-2-ollb
Tetrahedron: Asymmetry, 1991Co-Authors: John M. Mcintosh, Kenneth C. CassidyAbstract:Abstract Dissolving metal reduction of known enone S affords predominantly the racemic form of title ketone ( 3 ) whereas catalytic reduction gives the Meso Isomer 6 . Neither ketone 3 nor alcohol 4 could be satisfactorily resolved. Asymmetric synthesis of (−)− 3 and (+)− 4 (ee=91 %) was effected from ketone (+)- 13 .
Anubendu Adhikary - One of the best experts on this subject based on the ideXlab platform.
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Configurational Stability and Stereochemistry of P-Stereogenic Nickel POCOP-Pincer Complexes
Organometallics, 2015Co-Authors: Anubendu Adhikary, Jeanette A. Krause, Hairong GuanAbstract:The P-stereogenic nickel complex {2,6-[(t-Bu)(Ph)PO]2C6H3}NiCl (2) has been synthesized via cyclometalation of the POCOP-pincer ligand 1,3-[(t-Bu)(Ph)PO]2C6H4 (1) with NiCl2. The initially isolated 2 consists of a 1:1 mixture of racemic and Meso Isomers that are separable through repeated crystallization and is configurationally stable even at 110 °C. Upon mixing with t-BuOK, the Meso Isomer (2-Meso) displays a higher ligand substitution rate than the racemic Isomer (2-rac), likely because its nickel center is sterically more accessible. Complex 2, as either pure 2-rac or a 2-rac/2-Meso mixture, can be converted to the nickel triflate complex {2,6-[(t-Bu)(Ph)PO]2C6H3}NiOTf (3) or the nickel formate complex {2,6-[(t-Bu)(Ph)PO]2C6H3}NiOCHO (7) without epimerization at the phosphorus centers. Under a dynamic vacuum at 90 °C, decarboxylation of 7-Meso is faster than that of 7-rac, suggesting that in the transition state the formato hydrogen approaches the nickel center from the axial site rather than the equa...
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Configurational Stability and Stereochemistry of P‑Stereogenic Nickel POCOP-Pincer Complexes
2015Co-Authors: Anubendu Adhikary, Jeanette A. Krause, Hairong GuanAbstract:The P-stereogenic nickel complex {2,6-[(t-Bu)(Ph)PO]2C6H3}NiCl (2) has been synthesized via cyclometalation of the POCOP-pincer ligand 1,3-[(t-Bu)(Ph)PO]2C6H4 (1) with NiCl2. The initially isolated 2 consists of a 1:1 mixture of racemic and Meso Isomers that are separable through repeated crystallization and is configurationally stable even at 110 °C. Upon mixing with t-BuOK, the Meso Isomer (2-Meso) displays a higher ligand substitution rate than the racemic Isomer (2-rac), likely because its nickel center is sterically more accessible. Complex 2, as either pure 2-rac or a 2-rac/2-Meso mixture, can be converted to the nickel triflate complex {2,6-[(t-Bu)(Ph)PO]2C6H3}NiOTf (3) or the nickel formate complex {2,6-[(t-Bu)(Ph)PO]2C6H3}NiOCHO (7) without epimerization at the phosphorus centers. Under a dynamic vacuum at 90 °C, decarboxylation of 7-Meso is faster than that of 7-rac, suggesting that in the transition state the formato hydrogen approaches the nickel center from the axial site rather than the equatorial site. The structure of 2-rac has been studied by X-ray crystallography