432. | [2,3]-Wittig Rearrangement J. Cast et al., J. Chem. Soc. 1960, 3521; U. Schöllkopf, K. Fellenberger, Ber. 698, 80 (1966); Y. Makisumi, S. Notzumoto, Tetrahedron Letters 1966, 6393. [2,3]-Sigmatropic rearrangement of the conjugate bases of allylic ethers with high regioselectivity. The stereoselectivity is highly dependent on the nature of the substrate: Methods development for ring contractions generating enediynes: H. Audrain et al., Tetrahedron 50, 1469 (1994). Review of stereoselectivity: K. Mikami, T. Nakai, Synthesis 1994, 594. Reviews: J. A. Marshall, Comp. Org. Syn. 3, 975-1014 (1991); T. Nakai, K. Mikami, Org. React. 46, 105-209 (1994). Cf. Meisenheimer Rearrangements; Mislow-Evans Rearrangement; Sommelet-Hauser Rearrangement. |