Quantitative measures of solvent polarity.

Degradation and stabilization of poly (vinyl chloride). V. Reaction mechanism of poly(vinyl chloride) degradation

New gold-catalyzed [4+3]-annulations of 3-en-1-ynamides with isoxazoles afford 4H-azepines efficiently; this process involves 6π electrocyclizations of gold-stabilized 3-azaheptatrienyl cations. In the presence of Zn(OTf)2, the resulting 4H-azepines undergo skeletal rearrangement to furnish substituted pyridine derivatives. We subsequently develop new catalytic [4+2]-annulations between the same 3-en-1-ynamides and isoxazoles to deliver substituted pyridine products using Au(i)/Zn(ii) catalysts. This work reports the first success of the 6π electrocyclizations of heptatrienyl cations that are unprecedented in literature reports.

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Gold-catalyzed [4+3]- and [4+2]-annulations of 3-en-1-ynamides with isoxazoles via novel 6π-electrocyclizations of 3-azahepta trienyl cations

The four geometrical isomers of 1,3,5-undecatriene, 1a–d have been prepared (stereospecifically and non-stereospecifically), using either (1) the Wittig reaction, (2) thermal sigmatropic hydrogen shifts, (3) partial reduction of triple bonds by zinc, or (4) organocopper reagents. The thermal behaviour of the four 1,3,5-undecatrienes has been investigated and the products formed have been characterized. The spectra of 1a–d, and of related compounds, have been discussed in order to corroborate their configurational assignment.

The four isomeric 1,3,5-undecatrienes. Synthesis and configurational assignment.

The highly stereoselective asymmetric 6π-azaelectrocyclization was achieved as a general synthetic method based on the reaction between the (E)-3-carbonyl-2,4,6-trienal compounds and the (−)-7-alkyl-cis-1-amino-2-indanol derivatives which are effective chiral amines. The 7-alkyl-substituted 2-indanol moiety of the cyclized products was efficiently removed by the novel manganese dioxide oxidation under remarkably mild conditions, and the method was successfully applied to the formal synthesis of optically active 20-epiuleine.

Development of Highly Stereoselective Asymmetric 6π-Azaelectrocyclization of Conformationally Flexible Linear 1-Azatrienes. From Determination of Multifunctional Chiral Amines, 7-Alkyl cis-1-Amino-2-indanols, to Application as a New Synthetic Strategy: Formal Synthesis of 20-Epiuleine

Bruce Schatz

Papers

Thermal valence isomerizations: stereochemistry of the 2,4,6-octatriene to 5,6-dimethyl-1,3-cyclohexadiene ring closure

Electrocyclic reactions : Stereochemistry of the triene electrocyclization

The abnormal claisen rearrangement II. High temperature chemistry of 1-ethyl-2-methylspiro[2,5]octa-4, 6-dien-8-one