Efficient route to 4H-1,3-oxazines through ring expansion of isoxazoles by rhodium carbenoids.
Studies related to the total synthesis of elisabethin C led to the discovery of a rhodium-catalyzed cascade sequence involving isoxazole ring expansion and a [4 + 3] cycloaddition. The scope of the isoxazole ring expansion was explored, resulting in the synthesis of a range of 4H-1,3-oxazines in 47-96% yield.
Manning
James R
JR
Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York, 14260-3000.
Davies
Huw M L
HM