Deprotonation and subsequent alkylation of 3,4-dihydro-6-(para-toluenesulfonylmethyl)-2H-pyran gives monoalkylated products in good yields, with excellent α selectivity. The alkylation succeeds not only for reactive haloalkanes, but also for simple primary and secondary alkyl bromides. Desulfonylation with sodium amalgam provides a new and simple route to substituted dihydropyrans.
对 3,4-二氢-6-(
对甲苯磺酸甲基)-
2H-吡喃进行去质子化和随后的烷基化反应,可获得单烷基化产品,产量高,δ选择性极佳。这种烷基化反应不仅适用于活性卤代
烷烃,也适用于简单的伯烷基和仲烷基
溴。用
钠汞齐进行脱磺化反应为获得取代的二氢
吡喃提供了一条新的简单途径。