Total Synthesis of Hemibrevetoxin Β via the Allylic Tin Methodology

Kadota, Isao; Yamamoto, Yoshinori

doi:10.1515/mgmc.1996.19.6.361

Cited by 5 publications

(3 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In particular, the thermal reactions of 14 and 15 did not afford the cyclized product at all (entries 5 and 9). It was rather surprising for us to observe the inefficient thermal cyclization of the acyclic systems 14 and 15 , since the cyclization to a 7-membered ring in the cyclic systems proceeded very well in respect to the chemical yield and stereoselectivity. − Perhaps, in contrast to 6-membered ring formation, the cyclization to a 7-membered ring requires a certain constrained system in order to bring the γ-carbon of allylic stannane close to the aldehyde.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Intramolecular Reaction of (γ-Alkoxyallyl)stannane with Aldehyde: Origin of the Stereoselectivities

et al. 1997

Self Cite

View full text Add to dashboard Cite

The intramolecular cyclization of simple acyclic (gamma-alkoxyallyl)stannane aldehydes 1, 2, and 12-15 was investigated to elucidate the relationship between the geometry of the double bond of the allylstannanes, the ring size of cyclic ethers produced by the cyclization, and the procedures for promoting the cyclization. The Lewis acid-mediated cyclization of 1-2, 12-13, and 14-15 gave the trans cyclic ethers 3, 39, and 41, respectively, either predominantly or exclusively irrespective of the geometry of the double bond and of the ring size of the cyclic ethers. The relationship in the thermal cyclization of 1 and 2, which gave the 6-membered cyclic ethers 4 and 3, was straightforward; the Z isomer 1 gave the cis product 4, and the E isomer 2 afforded the trans product 3. However, the relationship in the thermal cyclization of 12 and 13 which afforded the 5-membered cyclic ethers 39 and 40 was different from that expected from the cyclization via the well-accepted cyclic transition state, as observed in the case of 1 and 2. Both the Z (12) and E (13) isomers gave the cis cyclic ether 40 either predominantly or exclusively. The protic acid-mediated (or -catalyzed) cyclization of 12-13 and 14-15 gave the trans cyclic ethers 39 and 41, respectively, regardless of the geometry of the double bonds. On the other hand, the protic acid-promoted cyclization of 1 and 2 was very strange; the Z isomer 1 gave the cis isomer 4, and the E isomer 2 afforded the trans isomer 3. The mechanisms for these cyclization reactions are proposed.

show abstract

Section: Resultsmentioning

confidence: 99%

“…We developed a new strategy for the construction of cyclic ether via the intramolecular condensation of allylstannane with aldehyde . As demonstrated by the total synthesis of hemibrevetoxin B and related polycyclic ethers, this route is efficient for the stereocontrolled construction of 7-membered cyclic ethers.…”

Section: Introductionmentioning

confidence: 99%

Intramolecular Reaction of (γ-Alkoxyallyl)stannane with Aldehyde: Origin of the Stereoselectivities

et al. 1997

Self Cite

View full text Add to dashboard Cite

show abstract

“…We developed a new strategy for the construction of cyclic ethers via the intramolecular condensation of allylstannane with aldehyde . The usefulness of this methodology was demonstrated by the total synthesis of hemibrevetoxin B and related polycyclic ethers. , To expand the scope of the heterocycle synthesis via allylic stannanes, we aimed at replacing the oxygen atom of aldehyde by a nitrogen atom, because the allylation of imines has been well studied as well as that of aldehydes, and the replacement of aldehydes (CO double bond) to CN double bond would give β-amino cyclic ethers.…”

Section: Introductionmentioning

confidence: 99%

Diastereo- and Enantioselective Synthesis of β-Amino Cyclic Ethers via the Intramolecular Reaction of γ-Alkoxyallylstannane with Imine

1999

Self Cite

View full text Add to dashboard Cite

The intramolecular Lewis acid mediated cyclization of gamma-alkoxyallylstannanes 1, 2, and 14, bearing a hydrazone group at the terminus of the carbon chain, afforded exclusively the corresponding trans beta-amino cyclic ethers 3a, 4a, and 15, respectively. The Lewis acid mediated cyclization of gamma-alkoxyallylstannane 5, having (R)-(+)-1-phenylethylamine as a chiral auxiliary, afforded exclusively trans beta-amino cyclic ether 6a with very high diastereomeric excess (de) in very high chemical yields. The asymmetric cyclization of gamma-alkoxyallylstannane with imine 7 in the presence of chiral titanium-BINOL complex 9, afforded predominantly cis beta-amino cyclic ether 8b with high enantiomeric excess (ee). The chiral Lewis acid mediated cyclization of racemic compound 38 containing phenyl as a substituent afforded cis isomer 39 with very high enantiomeric excess (ee).

show abstract

Bicyclic 6-6 Systems: Two Heteroatoms 1:1

Dobbs

2008

Comprehensive Heterocyclic Chemistry III

View full text Add to dashboard Cite

Total Synthesis of Hemibrevetoxin Β via the Allylic Tin Methodology

Cited by 5 publications

References 6 publications

Intramolecular Reaction of (γ-Alkoxyallyl)stannane with Aldehyde: Origin of the Stereoselectivities

Intramolecular Reaction of (γ-Alkoxyallyl)stannane with Aldehyde: Origin of the Stereoselectivities

Diastereo- and Enantioselective Synthesis of β-Amino Cyclic Ethers via the Intramolecular Reaction of γ-Alkoxyallylstannane with Imine

Bicyclic 6-6 Systems: Two Heteroatoms 1:1

Contact Info

Product

Resources

About