Catalytic tin radical mediated tricyclisations. Part 2 †‡
作者:David R. Kelly、Mark R. Picton
DOI:10.1039/b000662i
日期:——
Propenyl 4-O-propargyl-, propargyl 4-O-propenyl-, and propargyl 4-O-propargyl-2,3-dideoxy-α-D-erythro-hex-2-enopyranosides undergo catalytic, tin radical initiated, cascade reactions, in which three rings are constructed in a single reaction. In each case, a lack of stereoselectivity in the second cyclisation results in an additional product which is produced non-catalytically. The dienes which result from catalytic cyclisation of propargyl 4-O-propargyl-2,3-dideoxy-α-D-erythro-hex-2-enopyranosides, undergo in situ hydrostannylation to give unusual allylstannanes.
4-O-丙炔基丙基、4-O-丙炔基丙基和 4-O-丙炔基丙基-2,3-二脱氧-α-D-赤式-己-2-烯吡喃糖苷发生了锡自由基引发的催化级联反应,在一次反应中生成了三个环。在每种情况下,由于第二次环化缺乏立体选择性,都会产生一种非催化的额外产物。丙炔基 4-O-丙炔基-2,3-二脱氧-α-D-赤式-己-2-烯吡喃糖苷催化环化产生的二烯会发生原位氢化反应,生成不常见的烯丙基锡。