Unexpected Formation of Highly Strained 2,5‐Dioxa‐3‐Silabicyclo[2.1.0]Pentane by the Reaction of Isolable Dialkylsilylene with Benzil

Abstract

ABSTRACTThe reaction of isolable dialkylsilylene 1 with benzil gave [1+4] cycloadduct 1,3‐dioxa‐2‐sila‐cyclopent‐4‐ene 2 and unexpected 2,5‐dioxa‐3‐silabicyclo[2.1.0]pentane derivative 3. Compound 3 slowly isomerized to 2. The global reaction route mapping method of the model compounds suggests that three reaction paths from an initial silylene–ketone complex (carbonyl silaylide) to 2. A large ring strain energy of model compound for 3 (3′) (218.9 kJ·mol−1) was estimated by density functional theory calculations.