Reversible Stannylenoid Formation from the Corresponding Stannylene and Cesium Fluoride

Abstract

AbstractA fluorostannylenoid (Cs+[R2SnF]− (9), R2=(TMS)2CCH2CH2C(TMS)2) was prepared by reacting a stable dialkylstannylene (R2Sn (8), R2=(TMS)2CCH2CH2C(TMS)2) with cesium fluoride at room temperature in THF. While 9 is stable in THF and DME, removal of the solvent leads to the regeneration of stannylene 8. No reaction occurred when 8 was treated with CsF in a hydrocarbon solvent. Addition of dibenzo‐21‐crown‐7 ether to the THF solution of stannylenoid 9 followed by usual workup affords the corresponding crystalline stannylenoid crown ether complex, the X‐ray structural analysis of which revealed a fluorine‐bridged contact ion‐pair structure. The reaction of 9 with excess phenylacetylene gives the corresponding di(phenylethynyl)stannane.