A Carbene Relay Strategy for Cascade Insertion Reactions

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Insertion reactions of metallocarbenes are crucial for α-heteroatom functionalization of carbonyl compounds.
• Existing methods are limited to introducing only a single heteroatom due to carbene precursor constraints.

Purpose of the Study:

• To develop a new synthetic strategy for sequential heteroatom insertion into carbonyl compounds.
• To overcome the limitations of single heteroatom introduction in existing methods.

Main Methods:

• Utilized a novel I(III)/S(VI) reagent for cascade heteroatom insertion.
• Employed transition metal catalysis with X-H bonds (X=O, N) and subsequent Y-H bonds (Y=S, N, O, C).
• Investigated various cascade reactions including double amidation and double insertion.

Main Results:

• Successfully synthesized symmetrical and unsymmetrical α,α-O,O-, α,α-O,N-, and α,α-N,N-substituted ketones.
• Demonstrated cascade reactions for CN/CN double amidation, C-H/C-S double insertion, and C-S/Y-H double insertion.
• Achieved simultaneous installation of up to three functional groups onto the α-carbon of carbonyl compounds in one step.

Conclusions:

• The developed I(III)/S(VI) reagent and cascade strategy offer a versatile approach for synthesizing complex carbonyl compounds.
• This method enables efficient introduction of multiple α-heteroatoms, expanding synthetic possibilities.
• The reactions proceed under mild conditions, making the methodology practical for various applications.