Methylenespiro[2.3]hexanes via Nickel-Catalyzed Cyclopropanations with [1.1.1]Propellane

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• [1.1.1]Propellane is a strained hydrocarbon known for addition reactions.
• Transition metal catalysis of [1.1.1]propellane is underdeveloped, yielding mixtures and poor selectivity.
• Existing methods lack synthetic utility for diverse bicyclo[1.1.1]pentane derivatives.

Purpose of the Study:

• To develop novel transition metal-catalyzed reactions of [1.1.1]propellane.
• To utilize [1.1.1]propellane as a carbene precursor for cyclopropanation.
• To synthesize methylenespiro[2.3]hexane products with high selectivity.

Main Methods:

• Nickel(0) catalysis was employed.
• Reaction of [1.1.1]propellane with functionalized alkenes.
• Computational studies were performed to elucidate the reaction mechanism.

Main Results:

• Nickel(0) catalysis enabled the use of [1.1.1]propellane as a carbene precursor.
• Selective synthesis of methylenespiro[2.3]hexane products was achieved.
• Computational studies supported a mechanism involving a Ni(0)-[1.1.1]propellane complex and a 3-methylenecyclobutylidene-nickel intermediate.

Conclusions:

• Nickel(0) catalysis provides a new synthetic utility for [1.1.1]propellane.
• This method offers selective access to methylenespiro[2.3]hexane derivatives.
• The developed catalytic system overcomes limitations of previous approaches.