Mixed boron trihalide adducts. A nuclear magnetic resonance study of donor site and halogen redistribution in boron trihalide adducts of methyl acetate and its sulphur analogues

Abstract

In methyl acetate and its mono- and di-thioanalogues, donation to the boron trihalides to form 1 : 1 complexes is from the carbonyl or thiocarbonyl group. Thus preference for the doubly bonded donor atom outweighs preferences previously noted between oxygen and sulphur as donor atoms. Complexes involving carbonyl and thiocarbonyl donation show contrasting behaviour which appears to be typical of oxygen and sulphur donation.