Photocatalytic Reaction of Aryl Halides with Tin(II) Acetate to Generate Arylstannane(IV) Reagents

Aromatic organotin(IV) compounds
are a valuable class
of reagents
widely used in cross-coupling reactions. However, the toxicity of
the most popular tributyl-substituted arylstannanes, combined with
complicated methods for their synthesis, imposes serious limitations.
Herein, we report an approach to accessing aryl organotin(IV) reagents
directly from aryl halides and cheap inorganic tin(II) acetate. The
insertion of tin(II) into the carbon–halogen bond is performed
under photocatalytic conditions and proceeds through the generation
of aryl radicals. The resulting organotin reagents may be directly
employed in Migita–Kosugi–Stille cross-coupling or can
be converted into conventional tributyltin compounds by treatment
with butylzinc bromide.

芳香族有机锡(IV)化合物（aromatic organotin(IV) compounds）是一类极具应用价值的试剂，广泛应用于交叉偶联反应中。然而，最为常用的三丁基取代芳基锡烷的毒性，加之其合成方法繁复，带来了诸多严重的应用局限。本文报道了一种直接以芳基卤化物与廉价无机乙酸锡(II)为原料制备芳基有机锡(IV)试剂的方法。该反应在光催化条件下将锡(II)插入碳卤键，反应历程涉及芳基自由基的生成。所得有机锡试剂可直接用于三田-小杉-斯蒂尔交叉偶联反应（Migita–Kosugi–Stille cross-coupling），也可通过与溴化丁基锌反应转化为常规三丁基锡类化合物。