Surefire generation of stannylpotassium: highly reactive stannyl anions and applications

Abstract

Organometallic reagents such as organolithium and Grignard reagents have long been esteemed in chemical synthesis for their exceptional reactivity. In contrast, the application of their sodium and potassium counterparts has been comparatively sluggish, notwithstanding their augmented reactivity stemming from their heightened ionic character. This inertia persists due to the constrained accessibility of these heavy alkali metal reagents. In this study, our focus was directed towards devising a convenient and pragmatic approach for fabricating heavy alkali metal-based reagents, particularly those grounded in potassium. Herein, we present a novel, direct method for generating stannylpotassium (Sn–K) reagents through the simple combination of readily available silylstannanes and t-BuOK. Subsequently, the generated Sn–K reagents were effectively harnessed for stannylative substitution of aryl halides, furnishing an array of arylstannanes straightforwardly under transition metal-free conditions. This application distinctly underscores the potential utility of highly reactive Sn–K species, hitherto sparingly tapped into within the realm of synthetic organic chemistry. Furthermore, our investigation confirms that Sn–K reagents manifest notably superior reactivity compared with their well-established stannyllithium (Sn–Li) counterparts. This heightened reactivity can be ascribed to the increasing ionic character of Sn–K, which was supported by computational experiments.