Transition‐Metal‐Free [4+3]‐Cycloaddition of
ortho
‐Quinone Methides and Isomünchnones: Catalytic and Diastereoselective Assembly of Oxa‐bridged Oxazocine Scaffolds
A transition-metal-free propargylation of ortho-quinone methides (o-QMs) with alkynyl zinc reagents was achieved. A conjugate alkynylation of an o-QM and subsequent cyclization sequence in the presence of KOt-Bu for the synthesis of 2,3-disubstituted benzofurans in one pot was developed. This efficient strategy exhibits good functional-group compatibility and gives moderate to good yields. The present reaction might serve as an attractive method for the synthesis of polysubstituted benzofurans.
A transition metal-free intermolecular redox-neutral β-alkylation of acyclic tertiary amines via borrowing hydrogen catalyzed by commercially available B(C6F5)3 was achieved.
A redox-neutral, transition-metal-free and photocatalytic protocol is developed for the synthesis of functionalized phenols from para-quinone methides.
A transition-metal free, proficient strategy for the one-pot synthesis of diverse diaryl methyl amino acid esters (DMAAEs) has been established from the easily accessible chiral amino acid esters and para-quinone methides (QMs) in very good to excellent yields.
An NHC-triggered, transition-metal-free strategy for the efficient synthesis of 2,3-disubstituted benzofuran derivatives in moderate to excellent yields from aryl or alkyl aldehydes and o-quinone methides has been developed.
A transition-metal-free radical carbonylation of activated alkylamines with thiophenols has been successfully developed. Various thioesters were selectively produced with moderate to good yields.