Tin triflate-promoted one-pot intramolecular annulation of α-geranyl or α-farnesyl β-ketosulfones 3–4 affords the respective bicyclic or tricyclic sulfonyl dihydropyrans 5–6 in moderate to good yields via a cascade cation-olefin-carbonyl carbocyclization process. The starting materials 3 and 4 were obtained by K2CO3-mediated α-geranylation or α-farnesylation of β-ketosulfones 1 with bromides 2a or
锡,
三氟甲磺酸促进的α -香叶基或一锅分子内成环α -法呢β-酮砜3 - 4次,得到相应的二环或
三环磺酰基二氢
吡喃5 - 6经由级联阳离子烯烃-羰carbocyclization过程在中度至良好的产率。原料3和4是通过K 2 CO 3介导的β-酮砜1与
溴化物2a或2b的α-香叶基化或α-法尼基化获得的。关键产物的结构通过X射线晶体学确认。