Preparation of Solid, Substituted Allylic Zinc Reagents and Their Reactions with Electrophiles
作者:Mario Ellwart、Paul Knochel
DOI:10.1002/anie.201504354
日期:2015.9.1
The treatment of various allylic chlorides or bromides with zinc dust in the presence of lithiumchloride and magnesium pivalate (Mg(OCOtBu)2) in THF affords allylic zinc reagents which, after evaporation of the solvent, produce solid zinc reagents that display excellent thermal stability. These allylic reagents undergo Pd‐catalyzed cross‐coupling reactions with PEPPSI‐IPent, as well as highly regioselective
在氯化锂和新戊酸镁(Mg(OCO t Bu)2)在THF中存在的情况下,用锌粉处理各种烯丙基氯化物或溴化物,可得到烯丙基锌试剂,该溶剂蒸发后,生成的固态锌试剂显示出优异的热稳定性。这些烯丙基试剂与PEPPSI-IPent进行Pd催化的交叉偶联反应,以及对芳基酮和醛进行高度区域选择性和非对映选择性的加成。酰化与各种酰氯区域选择性地产生相应的高烯丙基酮,用新的C C键总是被形成在烯丙基系统的最受阻碳。
Prins-pinacol spiroannulations
作者:Keith P. Minor、Larry E. Overman
DOI:10.1016/s0040-4020(97)90401-4
日期:1997.6
Lewisacid-promoted cyclizations of methylenecyclohexane siloxy acetals 14, 15, and 21 afford spiro[4.5]decanones 22, 25, and 29 in good yield. In all cases, exclusive pinacol rearrangement of C-1 of the original three-carbon acetal side chain is observed suggesting that pinacol rearrangement of the intermediate 9-decalyl cation occurs more rapidly than conformational equilibration. This selectivity
1-Bromo-1-lithioethene: A Practical Reagent for the Efficient Preparation of 2-Bromo-1-alken-3-ols
作者:Yehor Y. Novikov、Paul Sampson
DOI:10.1021/ol034594x
日期:2003.6.1
A reliable preparative-scale synthesis of 1-bromo-1-lithioethene is reported. This reagent undergoes clean 1,2-addition with a range of aldehydes and ketones at -105 degreesC to afford the corresponding 2-bromo-1-alken-3-ols in moderate to excellent yield. Efficient diastereoselective addition to alpha-siloxy and alpha-methylcyclohexanones, as well as protected 3-keto furanose sugars, is achieved in the presence of 10 mol % CeBr3. The resulting bromoallylic alcohol adducts have considerable potential as synthetic building blocks.
The stereoselective synthesis of acyclic and exocyclic trisubstituted olefins via a hydroxyl-directed Wittig reaction
作者:Philip Garner、Sarabu Ramakanth
DOI:10.1021/jo00388a063
日期:1987.6
Macrae,D.M.; Brook,A.G., Journal of Organometallic Chemistry, 1974, vol. 77, p. C19 - C21