allyl ethyl carbonates with isocyanides in the presence of a catalytic amount of Pd(OAc)2 provided ketenimines through β‐hydride elimination of the allyl imidoylpalladium intermediates. The insertion of the isocyanide into the π‐allyl Pd complex proceeded via an unusual η1‐allyl Pd species. The resulting ketenimines were hydrolyzed to β,γ‐unsaturated carboxamides during purification by flash column chromatography
Preparation of N-protected allylic amines and α-methylene-β-amino acids from vinylalumination/Baylis–Hillman products via tandem SN2′ substitution–Overman rearrangement
作者:P. Veeraraghavan Ramachandran、Thomas E. Burghardt、M. Venkat Ram Reddy
DOI:10.1016/j.tetlet.2005.01.110
日期:2005.3
reaction on the acetates obtained from vinylalumination or Baylis–Hillman products, followed by in situ reduction afforded allylicalcohols. Upon conversion to trichloroacetimidates and [3,3]-sigmatropic rearrangement, the corresponding N-protected β-substituted allylic amines were obtained in good yields. Utilization of hydroxy group as the nucleophile furnished allylic hydroxy esters, which were converted
S N 2'对由乙烯基铝化或Baylis-Hillman产品获得的乙酸盐进行反应,然后原位还原得到烯丙醇。在转化为三氯乙亚氨酸酯和[3,3]-σ重排后,以良好的产率获得了相应的N-保护的β-取代的烯丙基胺。利用羟基作为亲核试剂提供的烯丙基羟基酯,其通过超人重排转化为受保护的α-亚甲基-β-氨基酸。
Copper-Catalyzed Stereospecific Hydroboration of Internal Allylic Alcohols
作者:Enhui Ji、Haiwen Meng、Yue Zheng、Velayudham Ramadoss、Yahui Wang
DOI:10.1002/ejoc.201901435
日期:2019.11.30
Copper‐catalyzed highly stereospecific hydroboration of internal allylic alcohols using a silyl ether transient protection strategy is reported. This in situ protection effectively avoids the preferential side reaction of free hydroxyl group with boron reagent, thus promoting hydroboration. This method provides both the anti‐ and the syn‐ diastereomers of 1,3‐diols in high level of diastereomeric ratios
Asymmetric Allylboration of α,β-Enals as a Surrogate for the Enantioselective Synthesis of Allylic Amines and α-Amino Acids
作者:P. Veeraraghavan Ramachandran、Thomas E. Burghardt、M. Venkat Ram Reddy
DOI:10.1021/jo048144+
日期:2005.3.1
Optically pure allylic amines have been synthesized from α,β-unsaturated aldehydes via allylboration with (−)-B-allyldiisopinocampheylborane, followed by Overman rearrangement. By incorporating crotyl and alkoxyallylboration, functionalization at δ-position was readily accomplished. By applying this methodology, the synthesis of several chiral α-amino acids has been achieved.