High Regio-, Chemo-, and Stereoselectivity via Low-Temperature 4 + 3 Cycloadditions. Convergent Synthesis of Multifunctionalized Vinylmetals (M = Si, Sn) and S-Vinyl Benzenecarbothioates
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.
Stark, Christian B. W.; Pierau, Sabine; Wartchow, Rudolf, Chemistry - A European Journal, 2000, vol. 6, # 4, p. 684 - 691
作者:Stark, Christian B. W.、Pierau, Sabine、Wartchow, Rudolf、Hoffmann
DOI:——
日期:——
High Regio-, Chemo-, and Stereoselectivity via Low-Temperature 4 + 3 Cycloadditions. Convergent Synthesis of Multifunctionalized Vinylmetals (M = Si, Sn) and <i>S</i>-Vinyl Benzenecarbothioates
作者:Hartmut Beck、Christian B. W. Stark、H. Martin R. Hoffmann
DOI:10.1021/ol991386p
日期:2000.4.1
[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.