ChemInform Abstract: Copper(I) tert‐Butoxide‐Promoted 1,4 C^sp2‐to‐O Silyl Migration: Stereospecific Allylation of (Z)‐γ‐Trimethylsilyl Allylic Alcohols.

Abstract

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One-Pot Twofold Unsymmetrical C–Si Bond 2,6-Bifunctionalization of Arenes via Sequential [1,4]-Csp2 to O-Silyl Migration

“…We have already demonstrated the power of geminal bis(silanes) in organic synthesis by bifunctionalizing the two C−Si bonds. 6 Inspired by these studies, along with Smith', 7 Takeda's, 8 our own, 9 and others' 10 progress in cross-coupling based on Brook rearrangement involving Csp 2 to O-silyl migration, 11 as well as our recent synthesis of 2,6-di-(trimethylsilyl) benzaldehyde, 12 we wished to test the scenario in Scheme 1b. In this pathway, the hydroxyl group in 1 acts as an "on−off−on" switch to control each step in the sequential [1,4]-Csp 2 to O-silyl migration.…”

“…Syntheses of 8 and 9a−9c. 6-Bromo-3-(bromomethyl)-3methyl-8-(p-tolyl)isochromane (8). To a solution of 3ae (120 mg, 0.37 mmol) in MeCN (3 mL) was added NBS (166 mg, 0.93 mmol).…”

Copper-Catalyzed Regio- and Stereoselective Formal Hydro(borylmethylsilyl)ation of Internal Alkynes via Alkenyl-to-Alkyl 1,4-Copper Migration

“…15 To date, a related functionalization of methyl group on silicon via 1,n-metal migration is limited to a palladium-catalyzed process for a preinstalled MeR 2 Si-group on bromonaphthalenes via 1,5palladium migration. 4c In this context, as a new entry of 1,nmetal migration using a 3d transition metal, herein we describe the development of a copper-catalyzed regio-and stereo- selective synthesis of alkenylsilylmethylboronates 16,17 from unsymmetric internal alkynes and silylboronates by formal hydro(borylmethylsilyl)ation 12a −c,18 involving a 1,4-copper migration process from an alkenyl carbon to an alkyl carbon, 19,20 which has never been reported for any 3d transition metals (Scheme 1b).…”