Modeling chemical reactivity. 7. The effect of a change in rate-limiting step on the stereoselectivity of electrophilic addition to allylic alcohols and related chiral alkenes

Conference · Tue Feb 03 23:00:00 EST 1987 · J. Am. Chem. Soc.; (United States)

OSTI ID:6653622

Chamberlain, A R; Mulholland, Jr, R L; Kahn, S D; Hehre, W J

The stereoselectivities of electrophilic additions to acyclic allylic alcohols with and without internal nucleophiles have been assessed with use of previously developed chemical reactivity modeling techniques. Reactions normally assumed to proceed via onium-type intermediates have been investigated. The diastereofacial selectivity of attack by I/sub 2/, Br/sub 2/, PhSeCl, Hg(OAc)/sub 2/, and related electrophiles, known to be opposite for substrates containing an internal nucleophile compared with those without, is explained in terms of a change in the rate-limiting step for the reaction. Specifically, where intramolecular nucleophilic attack is possible, cyclizations proceed via a transition state that resembles a (reactant-like) ..pi.. complex, whereas reactions that involve intermolecular addition of the nucleophile are governed by one that resembles an onium ion, e.g., iodonium. Calculations show that these two extremes should exhibit opposite diastereofacial selectivity of attack on the acyclic allylic ..pi.. bond by the electrophile, in agreement with available experimental results.

• Research Organization: Univ. of California, Irvine
• OSTI ID: 6653622
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 109:3; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

090210 -- Alcohol Fuels-- Properties-- (1976-1989)
10 SYNTHETIC FUELS
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALCOHOLS
ALKENES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CONFORMATIONAL CHANGES
DATA
HYDROCARBONS
HYDROXY COMPOUNDS
INFORMATION
KINETICS
MATHEMATICAL MODELS
NUMERICAL DATA
ORGANIC COMPOUNDS
REACTION KINETICS
STEREOCHEMISTRY
THEORETICAL DATA