Silicon-directed acid ring-opening of allyltrimethylsilane oxide. X-ray structures of 3-triisopropylsilyl-2-(2,4-dinitrobenzoyloxy)-1-propanol and 3-triisopropylsilyl-2-(2,4,6-trinitrobenzoyloxy)-1-propanol

Allyltrimethylsilane oxide 5 undergoes regiospecific ring-opening with carboxylic acids in chloroform to give the hydroxy esters 6a-e. In polar solvents competing elimination results in the formation of allyl alcohol. Allyltriisopropylsilane oxide 17 undergoes analogous reactions as 5 in chloroform but does not undergo elimination in methanol or acetone. The X-ray structures of 18b and 18c reveal significant lengthening of the C-O (ester) bond (a remarkable 1.502(2) Angstrom for 18c), these structural effects are due to strong sigma(C-Si)-sigma*(C-O) interactions, particularly for 18c. (C) 1999 Elsevier Science S.A. All rights reserved.