Efficient Cross-Coupling Reactions of (Pivaloyloxymethyl)zinc Chloride

Abstract

(Pivaloyloxymethyl)zinc chloride, obtained by an iodine-magnesium exchange and subsequent transmetalation, shows a much higher reactivity in Negishi cross-couplings than the corresponding zinc organometallic, prepared by direct zinc insertion. Furthermore, a substituted derivative of (pivaloyloxymethyl)zinc chloride is prepared starting from pivaloyloxymethyl sulfoxide using TMPZnCl•LiCl (TMP = 2,2,6,6-tetramethylpiperidyl), followed by a sulfoxide-magnesium exchange.

Silyloxymethylation of Aryl Halides via Metallaphotoredox Catalyzed Desulfinative Cross‐Coupling with Silyl Rongalite

“…Broader access to oxymethylated arenes with defined positional selectivity may be feasible by employing aryl halide substrates that are more readily available than the corresponding aryl nucleophiles. Indeed, this approach has been practiced by the palladiumcatalyzed cross-coupling with various C1 nucleophiles derived from organotin, [8] -boron, [9] and -zinc reagents [10] to bring about the "programmed" introduction of a methyl unit having oxygen functionalities such as hydroxy, alkoxy, aryloxy, and acyloxy groups (Scheme 1A). [11] While a wide range of aryl substrates have been employed for the one-carbon appending reaction, cumbersome preparation of adorned C1 nucleophiles along with the sensitivity of the classical cross-coupling conditions remains a difficulty for general implementation.…”