Highly Enantiospecific Platinum-Catalyzed Cycloisomerizations: Synthesis of Enantioenriched Oxabicycloheptene Derivatives

Enantiospecific cycloisomerizations of 1,6-enynes to form oxabicyclo[4.1.0]heptene derivatives are described. Enantiospecificity is consistently high regardless of alkene or alkyne substitution, providing a general approach to greatly enantioenriched cyclopropanes. Additionally, a model for stereochemical transfer is proposed

Highly Enantiospecific Platinum-Catalyzed Cycloisomerizations: Synthesis of Enantioenriched Oxabicycloheptene Derivatives

Enantiospecific cycloisomerizations of 1,6-enynes to form oxabicyclo[4.1.0]heptene derivatives are described. Enantiospecificity is consistently high regardless of alkene or alkyne substitution, providing a general approach to greatly enantioenriched cyclopropanes. Additionally, a model for stereochemical transfer is proposed

Palladium-Catalyzed Hiyama Couplings of α-Silylenoates and α-Silylenamides

The Hiyama couplings of both α-silylenoates and α-silylenamides are described. These sensitive substrate classes require particularly specific conditions, employing both appropriate silicon-based species and a silver additive to realize high yields of the coupling products. Regioselective platinum-catalyzed hydrosilylations provide a direct and convenient entry into these stereodefined trisubstituted alkenes

Vicinal Bisheterocyclizations of Alkynes via Nucleophilic Interception of a Catalytic Platinum Carbene

A novel platinum-catalyzed double heterocyclization of propargylic ethers is described. The transformation exploits the intermediacy of a key α,β-unsaturated carbene. The reactivity of this carbene is such that systems can be developed which avoid a complicating 1,2-hydrogen migration, allowing remarkable versatility in the selective syntheses of oxygen- and nitrogen-containing vicinal bis-heterocyclic compounds

Correction to “Vicinal Bisheterocyclizations of Alkynes via Nucleophilic Interception of a Catalytic Platinum Carbene”

Correction to “Vicinal Bisheterocyclizations of Alkynes via Nucleophilic Interception of a Catalytic Platinum Carbene

Palladium-Catalyzed Hiyama Couplings of α-Silylenoates and α-Silylenamides

The Hiyama couplings of both α-silylenoates and α-silylenamides are described. These sensitive substrate classes require particularly specific conditions, employing both appropriate silicon-based species and a silver additive to realize high yields of the coupling products. Regioselective platinum-catalyzed hydrosilylations provide a direct and convenient entry into these stereodefined trisubstituted alkenes

Complementary Stereochemical Outcomes in Proline-Based Self-Regenerations of Stereocenters

Stereoselective alkylations of proline-based amino amides are described, where high levels of either a <i>cis</i> or <i>trans</i> configuration can be attained simply by the choice of the aminal group. Isobutryaldehyde-derived aminals provide the <i>cis</i> configuration, while 1-naphthaldehyde-derived aminals engender the complementary <i>trans</i> configuration

Complementary Stereochemical Outcomes in Proline-Based Self-Regenerations of Stereocenters

Stereoselective alkylations of proline-based amino amides are described, where high levels of either a <i>cis</i> or <i>trans</i> configuration can be attained simply by the choice of the aminal group. Isobutryaldehyde-derived aminals provide the <i>cis</i> configuration, while 1-naphthaldehyde-derived aminals engender the complementary <i>trans</i> configuration

Total Synthesis of Gelsenicine via a Catalyzed Cycloisomerization Strategy

The first total synthesis of (±)-gelsenicine is reported. The synthetic route is highly efficient (13 steps), featuring (1) a pivotal metal-catalyzed isomerization/rearrangement process that forges the central core of the molecule and (2) two facile C–N bond-forming steps that establish the flanking heterocycles