Metal-free Sp~3C-H Activation In The Synthesis Of 4-alkyl-2-cyclopentene-1-ol Motif And Its Application In Natural Products

This thesis consists two sections.The first section introduced the formation of C-C bond via C-H activation and its application in organic synthesis in the form of reviews.The formation of C-C bond is of great important for Organic Chemistry,a very attractive way to meet this demand would be through C-H activation due to its atom-and step-economical.Both transition-metal catalysis and transition-metal-free C-H activation reaction are introduced.A very important emphasis is placed on C-H activation by metal carbenoids,this part mainly introduced classical X-H insertion reaction(including C-H bond,O-H bond,N-H bond,S-H bond)between diazo compounds.We also introduce some examples of transition-metal-free C-H activation reaction in recent years.The second part is the core of my thesis.We found a new method to synthesize 4-alkyl-2-cyclopentene-1-ol as key motif by using metal-free sp3 C-H activation.The synthetic strategy is to one-pot metal-free Aldol condensation/Yang cyclization reaction using dihydronbenzopyran-4-one diazo compounds as precursor to construct 4-alkyl-2-cyclopentene-1-ol motif,including selectively sp3 C-H addition to build two sp3 C-C bonds,two quaternary carbon atom,and tertiary alcohol.Our metal-free sp3 C-H activation to build two sp3 C-C bonds has rarely been reported.