Preparation of Asymmetric α-Ketophosphonates by [3, 3]-Sigmatropic Shift of Enolphosphonates

K Afarinkia, AJ Twist, H Yu

Index: Afarinkia, Kamyar; Twist, Andrew J.; Yu, Hiu-Wan Journal of Organic Chemistry, 2004 , vol. 69, # 19 p. 6500 - 6503

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Citation Number: 13

Abstract

Here, we report on a methodology for the C-allylation of α-ketophosphonates 2 via a [3,3]-sigmatropic shift of the corresponding allylenolphosphonates, 3 (Scheme 3). Furthermore, we will show that asymmetric α-ketophosphonates undergo this reaction with diastereoselectivity and that the selectivity in these reactions is influenced by chirality at the phosphorus. ... When heated at reflux in toluene, phosphoenols 5a−7a and 5b−7b underwent a clean and facile [3,3]-sigmatropic ...