Selective multiple methylene insertion reactions mediated by iodomethylzine iodide: Mechanistic considerations and synthetic applications

Article abstract of DOI:10.1016/S0040-4039(00)85980-8

The reaction of alkynylcoppers 1 with an excess of iodomethylzinc iodide selectively furnishes the quadruple methylene insertion copper organometallics 2 in fair to good yields. The mechanism of the reaction has been investigated and postulated intermediates such as 4 or 8 have been trapped with electrophiles like aldehydes or ketones in excellent yields. A new in situ preparation of propargylic copper derivatives 4 starting from readily available alkynylcopper compounds has been developed leading to homopropargylic alcohols in 80-95% yield.