Quinone Diazides for Olefin Functionalization

Abstract

The utility of quinone diazides in materials science is vast and well-documented, yet this potentially useful motif has languished in the annals of organic synthesis. Herein we show that modern tools of catalysis can be employed with free or suitably masked quinone diazides to unleash the power of these classic diazo compounds in the context of both inter- and intramolecular olefin cyclopropanation.

Cp*Rh(iii) and Cp*Ir(iii)-catalysed redox-neutral C–H arylation with quinone diazides: quick and facile synthesis of arylated phenols

“…[14] Structurally, quinone diazides can be regarded as carbonyl diazo compounds bearing two electronacceptors. [15,16] Therefore, a Rh-carbenoid was expected to be formed after the C-H activation event. Thereafter, by a subsequent -insertion and rearomatization, a direct C-H arylation reaction should be achieved (vide infra for a proposal of mechanism).…”

RhII‐Catalyzed Intermolecular C−H Arylation of Aromatics with Diazo Quinones

“…α‐Diazo carbonyl compounds have been reported to undergo C−H alkylation of arenes in the presence of transition‐metal catalysts presumable via addition of electron‐rich arenes to electrophilic metal carbenes . Diazo quinone, a carbonyl diazo compound bearing two electron acceptors, is expected to undergo similar electrophilic addition of a metal quinoid carbene to arenes to give a Wheland‐type intermediate II (Scheme ), which undergoes a hydrogen shift and rearomatization to lead to biaryls. The potential side reactions including Buchner reaction, dimerization of diazo quinone and over‐arylation pose major challenges to achieve intermolecular C−H arylation.…”

Recent Progress in Steroid Synthesis Triggered by the Emergence of New Catalytic Methods

“…Cyclopropane‐containing steroids such as cycloartenols represent challenging synthetic targets. In 2014, Baran and co‐workers reported a new approach to the synthesis of such steroids that is based on an intramolecular cylopropanation with quinone diazides using Rh(II)‐based catalysts and provided steroidal core 109 that may serve as the intermediate for the synthesis of cycloartenols and other classes of steroids…”

“…Rh(II)‐catalyzed intramolecular cyclopropanation in the synthesis of the cycloartenol core by the Baran group …”

“…In 2014, Baran and co-workers reported a new approach to the synthesis of such steroids that is based on an intramolecular cylopropanation with quinone diazides using Rh(II)-based catalysts and provided steroidal core 109 that may serve as the intermediate for the synthesis of cycloartenols and other classes of steroids. [43] These studies commenced with the preparation of the fragments 103 and 106 (Scheme 23). Thus, bromophenol derivative 101 was subjected to a 4 step sequence that involved Sonagashira coupling with TMS-protected acetylene (PdCl 2 (PPh 3 ) 2 , CuI), reduction of the nitro group (Zn, FeSO 4 ), and subsequent installation of the triazene moiety via the intermediacy of the diazonium salt (NaNO 2 , HCl then HNiPr 2 ).…”