Abstract
A new general synthetic approach to hydroquinone meroterpenoids is here described. The framework of the aforementioned natural compounds was built up through the Li2CuCl4 catalysed cross coupling reaction of the 4-substituted-(E)-prenyl acetates 9 with 2,5-bis(benzyloxy)phenyl magnesium bromide 8 as a key step. The latter sp3-sp2 coupling affords the products in good chemical yields and in very high stereoisomeric purity. A further key step of the present synthetic method consists of the removal of the benzylic protecting groups by a very mild procedure based on the use of lithium naphthalenide. The latter reagent, in combination with aliphatic dialkylamines, is able to cleave all the benzylic protecting groups leaving unaffected the polyenic moieties. By these means, we devised a new synthesis of the natural hydroquinone geranylhydroquinone, farnesylhydroquinone, metachromin V and alliodorol. In addition, the marine meroterpenoid, (+)-(S)-metachromin V, was synthesized for the first time; its chemical structure was confirmed and its absolute configuration was unambiguously assigned.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.