Hiroyuki Minakata

α-and γ-Substitution Reactions of Cyclic γ-Acetoxy-α,β-Unsaturated Esters with a Novel Reagent BuCu-AlCl3

Abstract Organocopper (I) reagents are useful for carbon-carbon bond formations and it has been amply demonstrated that α,β-unsaturated acids or esters and allylic acetates react with a variety of reagents to give conjugate adducts1,2) and substitution products3), respectively. However, little is known on the carbon-carbon bond formation of γ-acetoxy-α,β-unsaturated esters with organocopper (I) reagent.4) As part of a synthetic study directed towards toxic alkaloid with nerve-muscle activity, we required a butylated product starting from a cyclic γ-acetoxy-α,β-unsaturated ester. The unfortunate lack of reports on the reaction of cyclic γ-acetoxy-α,β-unsaturated esters with organocopper (I) reagent prompted us to describe our results on the reaction of cyclic γ-acetoxy-α,β-unsaturated esters with Bu2CuLi, BuCu, and a novel reagent BuCu-(AlCl3)n.∗1

A new synthesis of spirovetivanes via the spiro acyloin intermediate

Ethyl-3-(1-ethoxycarbonyl-2,6-dimethylcyclohex-2-enyl)propionate 5 was stereoselectively synthesized. The diester 5 was spiroannulated by the acyloin condensation to give the bis(tri-methylsiloxy) ...

Über die 1,4-addition von “RCu-AlCl3” an α,β-ungesättigte γ-tert.-butyldimethylsiloxy-ketone

Zusammenfassung An efficient procedure for the conjugate addition reaction of α,β-unsaturated γ-tert.-butyldimethylsiloxy-ketones with a novel reagent RCu-AlCl 3 was described.

A new stereoselective synthetic route to perhydrohistrionicotoxin

Abstract A stereoselective synthesis of rel -(6S,7S,8S) -7-butyl-8-hydroxy-1-azaspiro[5.5]undecan-2-one, a key intermediate for the synthesis of perhydrohistrionicotoxin, was described.

Effective method for the conjugate addition of γ-acetoxy-αβ-unsaturated ketones with RCu-AlCl3

An efficient procedure for the conjugate addition of γ-acetoxy-αβ-unsaturated ketones with RCu–AlCl3 is described.

Conformational Analysis of Four Stereoisomeric Methyl 3-Acetoxy-2-Butyl-1-Cyclohexanecarboxylates and Their Derivatives in Solution

Abstract The conformational analysis of six-membered ring compounds such as mono- and disubstituted cyclohexane is a well-documented subject, and hence prediction of the most stable conformation of a given compound can be in general achieved with reasonable accuracy either by use of thermodynamic data or by spectroscopic methods.1) When considering polysubstituted cyclohexane, the configurational and the conformationay possibilities become large. The conformational aspects of 1,2,3-trisubstituted cyclohexanes would be complex depending on the nature of substituents because so many parameters are involved.1)