Chemoselective Synthesis of <i>α,β</i> ‐Unsaturated Silyl Esters and Silyl Phosphonates over Cyclopropanation

α , β ‐Unsaturated silyl esters are an important class of compounds in organic, inorganic, and pharmaceutical chemistry, known for their versatility and unique reactivity. The conjugated system in these compounds enables Michael addition reactions, making them useful intermediates in the synthesis of complex organic/inorganic molecules, including pharmaceuticals, agrochemicals, and natural products. Having realized the importance of α , β ‐unsaturated silyl esters, a strategy has been devised to synthesize various functionalized allyl and vinyl silanes using diazo compounds and respective silanes. Herein, it has been demonstrated that the allyl and vinyl silanes can react with diazo compounds in a chemoselective manner offering a versatile method for constructing CC bond formation over the cyclopropanation reaction in the presence of 1 mol% of [Cp*RuCl 2 ] n as a catalyst under mild conditions. Direct CH bond functionalization of allyl and vinyl silanes with alpha diazo esters and phosphonate diazo showcases the adaptability of silicon‐based chemistry in modern organic synthesis. The plausible mechanism of the reaction has been realized with the help of density functional theory calculations. All the synthesized α , β ‐unsaturated silyl esters are isolated and characterized by using sophisticated analytical and spectroscopic techniques.