Allyl Silane Additions to Highly Electrophilic 5,6-Dihydro-2H-1,4- oxazinones

Allylsilane addition to the dihydro-2H-1,4-oxazinones, 1, proceeded in moderate to good yields with transdiastereoselectivity. The yield of addition reactions of 5-phenyl-5,6-dihydro-2H-1,4-oxazin-2-one with allylsilanes is improved over the corresponding additions of Grignard reagents to 1 and illustrates a simple path to protected β,β- disubstituted α-amino acids.