Progress in natural products synthesis via free radical reactions

Conference · Mon Sep 01 04:00:00 EDT 1986 · Am. Chem. Soc., Div. Pet. Chem., Gen. Pap., Prepr.; (United States)

OSTI ID:6772235

Curran, D P

The recent surge in the application of free radical reactions to topical problems in organic synthesis can be attributed to the many favorable characteristics of such reactions. The trial-kyltin hydride promoted reductive cyclization of 5-hexenyl halides and related substances provides a mild, selective and powerful method for construction of five- (and sometimes six-) membered rings. Such reactions frequently complement more traditional carbanion or carbocation approaches and offer unique advantages in many situations. The wealth of kinetic data available for free radical reactions from mechanistic studies is an invaluable tool to aid synthetic planning. As a class, condensed cyclopentanoid natural products have grown dramatically in both numbers and importance over the last decade. The authors are developing a general approach to the various classes of triquinanes (linear, angular, propellane) which employs a tandem radical cyclization as the key carbon-carbon bond forming step. With both linear and angular triquinanes, a double cyclization reaction will form the two outer rings about a central cyclopentene ring. Strategic design in this manner (as opposed to a triple cyclization of an acyclic precursor) allows rigid control of the ring fusion stereochemistry. In effect, this is a radical initiated polyolefinic cyclization and analogy to cation initiated polyolefinic cyclizations, which are so powerful in condensed cyclohexanoid synthesis, is apparent. Research is just being expanded to include the propellane class of polyquinanes.

• Research Organization: Dept. of Chemistry, Univ. of Pittsburgh, Pittsburgh, PA
• OSTI ID: 6772235
• Report Number(s): CONF-860911-
• Conference Information: Journal Name: Am. Chem. Soc., Div. Pet. Chem., Gen. Pap., Prepr.; (United States) Journal Volume: 31:3
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKANES
ALKENES
ALKYL RADICALS
ANIONS
AROMATICS
CATIONS
CHARGED PARTICLES
CHEMICAL PREPARATION
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CONDENSED AROMATICS
CONDENSED CYCLOALKANES
CYCLOALKANES
CYCLOHEXANE
DEHYDROCYCLIZATION
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
ION EXCHANGE
IONS
KINETICS
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
PENTENES
RADICALS
REACTION KINETICS
REDUCTION
STEREOCHEMISTRY
SYNTHESIS
TIN COMPOUNDS
TIN HYDRIDES
YIELDS