A stereodivergent strategy for the synthesis of skippeddienes is developed. The method consists of hydroboration of allenes and Migita-Kosugi-Stille coupling, which allows for access to all four possible stereoisomers of the skippeddienes. The hydroboration is especially useful for providing both E-allylic and Z-allylic alcohols from the same allene by simply changing the organoborane reagent. The
Regioselective Propargylation of Aldehydes and Ketones by Electrochemical Reaction using Zinc and Aluminum Anodes
作者:Nobuhito Kurono、Kazuya Sugita、Masao Tokuda
DOI:10.1016/s0040-4020(99)01089-3
日期:2000.2
Electrochemical propargylation of aldehydes and ketones with unsubstituted or α-substituted propargylic bromides using platinum cathode and zinc anode proceeded efficiently under mild conditions to give the corresponding homopropargyl alcohols exclusively in high yields. Similar electrochemical propargylation with γ-substituted propargyl bromides gave the corresponding homoallenyl alcohols as major
Studies on Pd(II)-Catalyzed Coupling−Cyclization of α- or β-Amino Allenes with Allylic Halides
作者:Shengming Ma、Fei Yu、Wenzhong Gao
DOI:10.1021/jo0342469
日期:2003.7.1
The palladium-catalyzed coupling-cyclization of alpha- or beta-amino allenes with allylic halides leading to 3-allylic 2,5-dihydropyrroles and 1,2,3,6-tetrahydropyridines, respectively, was studied. The starting materials are easily available. The skeletons of both two classes of products were established by the X-ray diffraction studies of 7i and 9b. Through the study of the reaction of 2b with 3-chloro-1-butene, 1-chloro-2-butene, and pi-allyl palladium species and the stereochemical outcome of the coupling cyclization of (S)-2m and (R)-2n, it is believed that the current transformation most likely proceeded via a Pd(II)-catalyzed pathway, although a Pd(0) pathway cannot be completely excluded.