High regio-, chemo-, and stereoselectivity via low-temperature 4+3 cycloadditions.: Convergent synthesis of multifunctionalized vinylmetals (M = Si, Sn) and S-vinyl benzenecarbothioates

被引:38
作者
Beck, H [1 ]
Stark, CBW [1 ]
Hoffmann, HMR [1 ]
机构
[1] Univ Hannover, Dept Organ Chem, D-30167 Hannover, Germany
关键词
D O I
10.1021/ol991386p
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
[GRAPHICS] A series of enantiomerically pure 8-oxabicyclo[3.2.1]oct-6-en-3-ones functionalized in the unsaturated two-carbon bridge has been prepared by the title reaction. Carbocation reactivity has been fined-tuned at -95 degrees C and adjusted to diene nucleophilicity. Conventional electrophilic substitution of 3-silylated and 3-stannylated furan is suppressed in favor of the rapid 4 + 3 cycloaddition mode. In the case of cycloadduct 13A, stereoselectivity (17:1) is perfectly matched to regioselectivity (17:1). High stereoselection as well as unprecedented regioselection and chemoselection is attributed to the low-temperature cycloaddition protocol and the design of chiral auxiliary and tether.
引用
收藏
页码:883 / 886
页数:4
相关论文
共 39 条
[31]  
2-Z
[32]  
Stark CBW, 1998, ANGEW CHEM INT EDIT, V37, P1266, DOI 10.1002/(SICI)1521-3773(19980518)37:9<1266::AID-ANIE1266>3.0.CO
[33]  
2-9
[34]   Synthesis of the C1-C9 segment of bryostatin [J].
Weiss, JM ;
Hoffmann, HMR .
TETRAHEDRON-ASYMMETRY, 1997, 8 (23) :3913-3920
[35]   Synthesis of dioxatricyclic segments of dictyoxetane.: Oxygenated 6,8-dimethyl-2,7-dioxatricyclo[4.2.1.03,8]nonanes show antitumor activity. [J].
Wittenberg, J ;
Beil, W ;
Hoffmann, HMR .
TETRAHEDRON LETTERS, 1998, 39 (45) :8259-8262
[36]  
Wolbers P, 1999, SYNLETT, P1808
[37]   Synthesis of the enantiopure C15-C26 segment of phorboxazole A and B [J].
Wolbers, P ;
Misske, AM ;
Hoffmann, HMR .
TETRAHEDRON LETTERS, 1999, 40 (24) :4527-4530
[38]  
Wolbers P, 1999, SYNTHESIS-STUTTGART, P797
[39]   trans-C-glycosides from 8-oxabicyclo[3.2.1]oct-6-en-3-one -: Synthesis of the C3-C13 segment of the phorboxazoles A and B [J].
Wolbers, P ;
Hoffmann, HMR .
TETRAHEDRON, 1999, 55 (07) :1905-1914