6-Exo and 7-endo photocyclization of αβ-unsaturated organosilicon ω-thiols
摘要:
The regioselectivity of cyclization of 3,3- and 4,4-dimethylsila-1-hexene-6-thiols upon UV-irradiation is reported. Ring closure involving the vinyl group at silicon results in the preferred formation of the exo-cyclic product, whereas a high and reversed regio- selectivity is observed when the cyclization reaction occurs via the allyl group at silicon.