A Chiral Sulfoxide-Ligated Ruthenium Complex for Asymmetric Catalysis: Enantio- and Regioselective Allylic Substitution

The design and synthesis of a novel chiral sulfoxide-ligated cyclopentadienyl ruthenium complex is described. Its utility as an asymmetric variant of [CpRu­(MeCN)₃]­PF₆ is demonstrated through its ability to function in the branched-selective asymmetric allylic alkylation of phenols and carboxylic acids. Water has also been shown to act as a competent nucleophile in this reaction to generate branched allyl alcohols with good regio- and enantioselectivities

Constructing Quaternary Stereogenic Centers Using Tertiary Organocuprates and Tertiary Radicals. Total Synthesis of <i>trans</i>-Clerodane Natural Products

A new concise construction of <i>trans</i>-clerodane diterpenoids is reported in which oxacyclic and <i>trans</i>-hydronaphthalene fragments are coupled, and the critical C9-quaternary carbon stereocenter formed stereoselectively, by 1,6-addition of a tertiary cuprate or a tertiary carbon radical to β-vinylbutenolide. This strategy is specifically illustrated by total syntheses of (−)-solidagolactone (<b>4</b>), (−)-16-hydroxycleroda-3,13-dien-15,16-olide (<b>5</b>, PL3), and (−)-annonene (<b>6</b>)

Correction to “Constructing Quaternary Stereogenic Centers Using Tertiary Organocuprates and Tertiary Radicals. Total Synthesis of <i>trans</i>-Clerodane Natural Products”

Correction to “Constructing Quaternary Stereogenic Centers Using Tertiary Organocuprates and Tertiary Radicals. Total Synthesis of <i>trans</i>-Clerodane Natural Products

Short Enantioselective Total Syntheses of <i>trans</i>-Clerodane Diterpenoids: Convergent Fragment Coupling Using a <i>trans</i>-Decalin Tertiary Radical Generated from a Tertiary Alcohol Precursor

The evolution of a convergent fragment-coupling strategy for the enantioselective total synthesis of <i>trans</i>-clerodane diterpenoids is described. The key bond construction is accomplished by 1,6-addition of a <i>trans</i>-decalin tertiary radical with 4-vinylfuran-2-one. The tertiary radical is optimally generated from the hemioxalate salt of the corresponding tertiary alcohol upon activation by visible light and an Ir­(III) photoredox catalyst. The enantioselective total synthesis of <i>trans</i>-clerodane diterpenoid <b>1</b> reported here was accomplished in seven steps from 3-methyl-2-cyclohexenone. The synthetic strategy described in this report allows a number of <i>trans</i>-clerodane diterpenoids to be synthesized in enantioselective fashion by synthetic sequences of 10 steps or less. This study illustrates a powerful tactic in organic synthesis in which a structurally complex target structure is disconnected at a quaternary carbon stereocenter to fragments of comparable complexity, which are united in the synthetic pathway by conjugate addition of a nucleophilic tertiary radical to a fragment harboring an electron-deficient C–C double bond