Reversal of the Regiochemistry in the Rhodium‐Catalyzed [4+3] Cycloaddition between Vinyldiazoacetates and Dienes

Abstract

A regio-, diastereo- and enantioselective [4+3] cycloaddition between vinylcarbenes and dienes has been achieved using the dirhodium tetracarboxylate catalyst Rh2(S-BTPCP)4. This methodology provides facile access to 1,4-cycloheptadienes that are regioisomers of those formed from the tandem cyclopropanation/Cope rearrangement reaction of vinylcarbenes with dienes.

Functionalizing the γ-position of α-diazo-β-ketoesters

“…Silyl enol ethers of α-diazo-β-ketoesters have proven to be useful synthetic intermediates in reaction with selected electrophiles, 17 and, with loss of the reactive diazo functionality, in rhodium-catalyzed enantioselective additions to enol ethers, 18 in rhodium-catalyzed cycloadditions with 1,3-dienes, 19 and other rhodium-catalyzed cycloadditions involving enol carbenoid intermediates. 20 …”

Cycloaddition reactions of enoldiazo compounds

“…Since the disclosure of tandem cyclopropanation/Cope rearrangement reactions, 135–153 the Davies group has been a major contributor to this area. Recently, they 154 and others 155 also developed [3+4]-methodologies that shared similar mechanistic pathways (vinylogous addition/ring closure) with the aforementioned [3+ n ]-cycloaddition reactions ( n = 1–3). Like the chemistry described in the previous two subsections, this field is dominated by dirhodium(II) catalysts, 135–152,154 although cooperation between rhodium and copper 153 as well as a gold-catalyzed reaction 155 have been observed and are included in the following subsection.…”

“…Whereas Rh 2 ( S -DOSP) 4 137,154 and Rh 2 ( S -PTAD) 4 138,154 preferentially induced rhodium-enolcarbenes to be attacked at their carbene carbon (to undergo the tandem cyclopropanation/Cope rearrangement sequences), sterically crowded tetrakis(triarylcyclopropanecarboxylate) dirhodium(II) catalysts have proven to be effective promoters of their vinylogous reactivity. The use of Rh 2 ( S -BTPCP) 4 in cycloaddition reactions of enoldiazoacetates 1 with 2-silyloxy-1,3-dienes 47 is illustrative (Scheme 22).…”

“…The use of Rh 2 ( S -BTPCP) 4 in cycloaddition reactions of enoldiazoacetates 1 with 2-silyloxy-1,3-dienes 47 is illustrative (Scheme 22). 154 Nucleophilic attack by the dienes at the vinylogous position of rhodium-enolcarbenes produced enantioenriched 1,4-cycloheptadiene derivatives 48 , rather than forming their regioisomers ( 46 -type cycloadducts) by reaction at the carbene carbon.…”

The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2014

“…;(6) formation of cyclopentanes via a rhodium-catalyzed cascade process involving the reaction of vinyl diazoacetates with substituted allylic alcohols[1072]; (7) a formal rhodium-catalyzed [4+3] cycloaddition involving silyloxy dienes and α-vinyl-α-diazoesters proceeding through Michael addition to the vinylcarbene complex intermediate followed by ring closure[1073]; and (8) carbonyl ylide based dipolar cycloadditions[1074]. Several examples where a Group 9 carbene complex-mediated reaction culminates in a rearrangement Cope rearrangement (e.g.…”