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Crystal structures of 3,6-di-allyl-tetra-cyclo[6.3.0.0(4,11).0(5,9)]undeca-2,7-dione and 1,7-di-allyl-penta-cyclo-[5.4.0.0(2,6). 0(3,10).0(5,9)]undecane-8,11-dione: allyl-ated caged compounds.

Kotha S, Seema V, Deodhar D, Shaikh M - Acta Crystallogr Sect E Struct Rep Online (2014)

Bottom Line: In (1), the carbon atoms bearing the allyl groups are far apart [2.9417 (17) Å], hence the expected ring-closing metathesis (RCM) protocol failed to give a ring-closing product.When these carbon atoms are connected by a C-C bond as in (2), the distance between them is much smaller [1.611 (3) Å] and consequently the RCM process was successful.In the crystal of (2), mol-ecules are linked via C-H⋯O hydrogen bonds forming chains along [100].

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Affiliation: Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai 400 076, India.

ABSTRACT
The title compounds, C17H20O2 (1) and C17H18O2 (2), are allyl-ated caged compounds. In (1), the carbon atoms bearing the allyl groups are far apart [2.9417 (17) Å], hence the expected ring-closing metathesis (RCM) protocol failed to give a ring-closing product. When these carbon atoms are connected by a C-C bond as in (2), the distance between them is much smaller [1.611 (3) Å] and consequently the RCM process was successful. The caged carbon skeleton of (1) can be described as a fusion of four five-membered rings and one six-membered ring. All four five-membered rings exhibit envelope conformations. The structure of compound (2) consists of four five-membered rings, of which two are cyclo-penta-none rings bonded at the 2, 4 and 5 positions and linked at the 3-carbons by a methyl-ene bridge. It also consists of one four-membered and two six-membered rings. All four five-membered rings adopt envelope conformations. In the crystal of (1), mol-ecules are linked via C-H⋯O hydrogen bonds, forming sheets lying parallel to (010). In the crystal of (2), mol-ecules are linked via C-H⋯O hydrogen bonds forming chains along [100].

No MeSH data available.


Various Grubbs catalysts used for ring-closing metathesis (RCM).
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fig2: Various Grubbs catalysts used for ring-closing metathesis (RCM).

Mentions: When diallyl tetra­cyclic dione (1) was subjected to ring-closing metathesis (RCM), the expected ring-closing product (3) was not obtained, Fig. 1 ▶. Whereas, compound (2) successfully underwent RCM to yield the desired ring-closing product (4), see Fig. 1 ▶. Further, when compound (1) was subjected to cross metathesis (CM) with but-2-ene-1,4-diallyl acetate (7) in the presence of Grubbs catalyst (Fig. 2 ▶), the di­acetate (5) was formed in 55% yield. Under similar reaction conditions, the penta­cyclic dione (2) did not deliver the cross-coupled product (6), but instead the RCM product (4) was formed, see Fig. 1 ▶. To gain insight about these observations, the crystal structure determinations of compounds (1) and (2) were undertaken.


Crystal structures of 3,6-di-allyl-tetra-cyclo[6.3.0.0(4,11).0(5,9)]undeca-2,7-dione and 1,7-di-allyl-penta-cyclo-[5.4.0.0(2,6). 0(3,10).0(5,9)]undecane-8,11-dione: allyl-ated caged compounds.

Kotha S, Seema V, Deodhar D, Shaikh M - Acta Crystallogr Sect E Struct Rep Online (2014)

Various Grubbs catalysts used for ring-closing metathesis (RCM).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4257271&req=5

fig2: Various Grubbs catalysts used for ring-closing metathesis (RCM).
Mentions: When diallyl tetra­cyclic dione (1) was subjected to ring-closing metathesis (RCM), the expected ring-closing product (3) was not obtained, Fig. 1 ▶. Whereas, compound (2) successfully underwent RCM to yield the desired ring-closing product (4), see Fig. 1 ▶. Further, when compound (1) was subjected to cross metathesis (CM) with but-2-ene-1,4-diallyl acetate (7) in the presence of Grubbs catalyst (Fig. 2 ▶), the di­acetate (5) was formed in 55% yield. Under similar reaction conditions, the penta­cyclic dione (2) did not deliver the cross-coupled product (6), but instead the RCM product (4) was formed, see Fig. 1 ▶. To gain insight about these observations, the crystal structure determinations of compounds (1) and (2) were undertaken.

Bottom Line: In (1), the carbon atoms bearing the allyl groups are far apart [2.9417 (17) Å], hence the expected ring-closing metathesis (RCM) protocol failed to give a ring-closing product.When these carbon atoms are connected by a C-C bond as in (2), the distance between them is much smaller [1.611 (3) Å] and consequently the RCM process was successful.In the crystal of (2), mol-ecules are linked via C-H⋯O hydrogen bonds forming chains along [100].

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai 400 076, India.

ABSTRACT
The title compounds, C17H20O2 (1) and C17H18O2 (2), are allyl-ated caged compounds. In (1), the carbon atoms bearing the allyl groups are far apart [2.9417 (17) Å], hence the expected ring-closing metathesis (RCM) protocol failed to give a ring-closing product. When these carbon atoms are connected by a C-C bond as in (2), the distance between them is much smaller [1.611 (3) Å] and consequently the RCM process was successful. The caged carbon skeleton of (1) can be described as a fusion of four five-membered rings and one six-membered ring. All four five-membered rings exhibit envelope conformations. The structure of compound (2) consists of four five-membered rings, of which two are cyclo-penta-none rings bonded at the 2, 4 and 5 positions and linked at the 3-carbons by a methyl-ene bridge. It also consists of one four-membered and two six-membered rings. All four five-membered rings adopt envelope conformations. In the crystal of (1), mol-ecules are linked via C-H⋯O hydrogen bonds, forming sheets lying parallel to (010). In the crystal of (2), mol-ecules are linked via C-H⋯O hydrogen bonds forming chains along [100].

No MeSH data available.