Isomers and 2,3-Sila-wittig Rearrangement of (Allyloxy)silylithium Silylenoid in the Gas Phase and THF Solvent

摘要

Theoretical calculations of the [2,3]-sila-wittig rearrangement of isomers of [(allyl-oxy)silyl]lithium (C3H50)H2SiLi have been performed in the gas phase and THF solvent using theG3MP2B3 method.Seven isomers of silylenoid (C3H5O)H2SiLi, 1～7, are found.The [2,3]-sila-wittig rearrangement paths are followed using two isomers, 2 and 4, to yield the transition states as well as the products.In the transition state, the silicon center functions as a nucleophile and the allyl as an electrophile.The interaction between the silicon and allylic sites leads to the formation of Si-C[3] bond and the break of O-C[1] bond.Finally, the (allylsilyl)oxylithium (C3H5)H2SiOLi is obtained.The rearrangement paths are confirmed by the intrinsic reaction coordinate (IRC)calculations.The rearrangement mechanisms of reactions of 2 and 4 are similar, and the latter reaction is more favored in the gas phase and THF solvent.Also, the solvent effects are analyzed in this work.