Stereocontrolled intramolecular cyclization of ω-tributylstannyl ether aldehydes. synthesis of the 6·7·7·6 ring system of polycyclic ethers
作者:Yoshinori Yamamoto、Jun-ichi Yamada、Isao Kadota
DOI:10.1016/0040-4039(91)85042-4
日期:1991.11
γ-oxo-substituted allylic tin (1) having an aldehyde group at the terminus of the carbon chain proceeded in a stereocontrolled manner to give the 7-membered β-hydroxy cyclic ether (2a) with high diastereoselectivity. This method was applied for the synthesis of the 6·7·7·6 ringsystem (3a).
natural polyether toxins contain the trans-pyran ladder structure. We describe a synthesis of the polyether trans-pyran ring system by using cationic gold(I)-catalyzed cyclization. This gold(I)-catalyzed cyclization provided high diastereoselectivity and high turnover. This method is expected to be applicable to the synthesis of polyethers.
We employed an iterative Pd(II)-catalyzed cyclization reaction to ether from tri-O-acetyl-D-glucal to synthesize trans-fusedpolyethers. This approach should be applicable to synthesize the core structure of marine ladder toxins.
Activation of 6-endo over 5-exo hydroxy epoxide openings. Stereoselective and ring selective synthesis of tetrahydrofuran and tetrahydropyran systems
作者:K. C. Nicolaou、C. V. C. Prasad、P. K. Somers、C. K. Hwang
DOI:10.1021/ja00196a043
日期:1989.7
Stereoselective synthesis of alcohols. Part LIII. (E)-γ-Alkoxyallylboronates: generation and application in intramolecular allylboration reactions
作者:Reinhard W. Hoffmann、Jochen Krüger、David Brückner
DOI:10.1039/b003551n
日期:——
subjected to the Matteson–Brown homologation with LiCH2Cl, give rise to the (E)-γ-alkoxyallylboronates 3 in good yield. This reaction sequence has been used to generate the (E)-γ-alkoxyallylboronates 14, 21, 26 and 31, which were the starting point for intramolecularallylborationreactions leading to the trans-disubstituted tetrahydropyrans 8 and 22, as well as hydrooxepans 27 and 32.