Catalyzed insertion reactions of substituted α-diazoesters. A new synthesis of cis-enoates

β‐Tosylamino and β‐Hydroxyl Substituted α‐Diazocarbonyl Compounds: X‐ray Structure and 1,2‐Migrations under Photochemical Condition

“…It is noted that in Rh 2 (OAc) 4 -catalyzed reaction of 1b, only cis product 10 was obtained. 6 The present work has confirmed that cis/trans isomerization occurred under photochemical condition, namely the trans product was possibly formed due to secondary photochemical reaction.…”

Rh-Catalyzed Intermolecular Reactions of Cyclic α-Diazocarbonyl Compounds with Selectivity over Tertiary C–H Bond Migration

“…However, the use of strongly electron deficient dirhodium tetrakis(trifluoroacetate), Rh 2 TFA 4 , 2b led to a precipitous loss of selectivity as butenolide 3a was formed in 78% yield with no cyclopropane detected. Consistent with previous findings, 17–20 a low yield (30%) and increased proportion of β-hydride elimination (43%) was observed in the Rh 2 (OPiv) 4 -catalyzed reaction performed at room temperature.…”

“…However, the reactivity of such diazo compounds can be relatively limited due to their propensity to undergo β-hydride migration to give alkene products. 2 The migratory aptitude of α-diazocarbonyl compounds ( I – III ) with β-C−H bonds follows the pattern displayed in Scheme 1a, with methine C−H bonds of III having the highest propensity for migration. Seminal studies on α-alkyl-α-diazocarbonyl compounds by Ganem 2a and McKervey 3 first established that β-hydride migration could be avoided in favor of intramolecular benzoate migration 2a, 4 and intermolecular S−H insertion.…”

“…2 The migratory aptitude of α-diazocarbonyl compounds ( I – III ) with β-C−H bonds follows the pattern displayed in Scheme 1a, with methine C−H bonds of III having the highest propensity for migration. Seminal studies on α-alkyl-α-diazocarbonyl compounds by Ganem 2a and McKervey 3 first established that β-hydride migration could be avoided in favor of intramolecular benzoate migration 2a, 4 and intermolecular S−H insertion. 3,5 Subsequently, Rh-catalyzed reactions of α-diazocarbonyl compounds with primary alkyl substitutents had been well demonstrated for a number of intramolecular processes.…”

Enantioselective Synthesis of Cyclobutanes via Sequential Rh-catalyzed Bicyclobutanation/Cu-catalyzed Homoconjugate Addition

“…15 Bicyclobutane carboxylates were first prepared from ethyl α-allyl-α-diazoacetate in seminal work by Ganem. 16 However, β-hydride migration was a significant side reaction. In recent years, our group 15 and that of Hashimoto 17 have developed intermolecular Rh-catalyzed transformations of α-alkyl-α-diazoesters that tolerate β-hydrogens, including reactions that produce cyclopropenes, cyclopropanes, dioxolanes, tetrahydrofurans and functionalized indoles.…”