Trost Barry M, Rudd Michael T, Costa Moisés Gulías, Lee Philip I, Pomerantz Andrew E
Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA.
Org Lett. 2004 Nov 11;6(23):4235-8. doi: 10.1021/ol048351w.
The ruthenium-catalyzed cycloisomerization of diynes containing one silyl alkyne and one propargyl alcohol yields 2-silyl-[6H]-pyrans instead of the expected unsaturated acylsilanes except when additional conjugation of a aromatic ring is present at the delta-position. Under certain conditions, a facile ruthenium-catalyzed isomerization of the product takes place as well. This regioselectivity of the cyclization can be controlled by the choice of solvent system. DFT calculations confirm the expected greater stability of the silyl-pyrans relative to the acylsilanes.
含一个硅烷基炔和一个炔丙醇的二炔的钌催化环异构化反应生成2-硅烷基-[6H]-吡喃，而非预期的不饱和酰基硅烷，但当δ-位存在芳环的额外共轭时除外。在某些条件下，产物也会发生钌催化的容易的异构化反应。环化反应的这种区域选择性可通过溶剂体系的选择来控制。密度泛函理论计算证实了预期的硅烷基吡喃相对于酰基硅烷具有更高的稳定性。
