Thioketene S,S-dioxides 2 were successfully generated through [3,3] sigmatropic rearrangement of alkynyl propargy] sulfones 1 and the formation of 2 was confirmed by trapping experiment using cyclohexene or allyltrimethylsilane affording a [2+2] cycloadduct 5. In situ generated thioketene S,S-dioxides 2 underwent facile conversion into allenynes 3 in moderate yields, via formation and subsequent [1,2] shift of vinylidene carbenes. (c) 2007 Elsevier Ltd. All rights reserved.
Palladium-Catalyzed Synthesis of Conjugated Allenynes via Decarboxylative Coupling
作者:Mary K. Smith、Jon A. Tunge
DOI:10.1021/acs.orglett.7b01751
日期:2017.10.20
A new strategy to access conjugated allenynes via a decarboxylativecoupling of propargyl esters of propiolates has been developed. In this process, allenyl-palladium intermediates are coupled with acetylides that are generated in situ to form the conjugated allenynes. Finally, the coupling is demonstrated to be highly stereospecific, providing a route to enantioenriched allenes.