Stereoselective β-hydroxy-α-amino acid synthesis via an ether-directed, palladium-catalysed aza-Claisen rearrangement
作者:Kate N. Fanning、Andrew G. Jamieson、Andrew Sutherland
DOI:10.1039/b510808j
日期:——
rearrangement of allylic acetimidates to effect the key step. This highly stereoselective process gave allylicamides in diastereomeric ratios of up to 14 : 1. Problems associated with the isolation of 1,3-products (anti-Claisen) from sterically demanding substrates via an insitu palladium(0)-catalysed rearrangement process were overcome by the addition of a re-oxidant, p-benzoquinone, leading to cleaner
Modified Julia olefination and α aminoxylation reactions mediated convergent synthesis of 1α, 24 (R)-dihydroxyvitamin D3 (tacalcitol)
作者:Andrea Martínez、Hugo Santalla、Fátima Garrido、Generosa Gómez、Yagamare Fall
DOI:10.1016/j.tetlet.2017.07.103
日期:2017.9
A convergent synthesis of tacalcitol has been achieved starting from inexpensive and commercially available isovaleraldehyde and easily available Inhoffen-Lythgoe diol. Key steps include a proline catalyzed α aminoxylation and a Julia-Kocienski olefination.