TY - JOUR
T1 - Transition Metal Catalyzed Radical Cyclizations
AU - Nagashima, Hideo
AU - Itoh, Kenji
PY - 1995
Y1 - 1995
N2 - Synthesis of trichlorinated γ-lactones or γ-lactams from allyl trichloroacetates or N-allyl trichloroacetamides was achieved by transition metal-catalyzed radical cyclizations. Treatment of these trichlorinated starting materials with a catalytic amount of cuprous salts or a ruthenium-phosphine complex resulted in cleavage of a carbon-chlorine bond and subsequent intramolecular addition of the carbon moiety and the chlorine atom to the carbon- carbon double bond. Stereochemistry of the product was similar to that observed in free radical cyclizations ; e.g. stereochemistry of β- and γ-substituents generated by the cyclization of 1-methyl-2-propenyl trichloroacetate was predominantly trans, whereas a cis-fuzed bicyclic lactone was formed by the reaction of 2-cyclohexenyl trichloroacetate. The cyclization of N-allyl trichloroacetamides offers a facile preparative method for pyrrolidinone derivatives from easily available allylic alcohols by the combination with the [3.3] -sigmatropic rearrangement of allyl trichloroimidates. It also provides an interesting entry to alkaloid skeletons. In the cyclization of N-substituted N-allyl trichloroacetamides, judicious choice of the N-substituent and the catalyst dramatically lowered the reaction temperature, and enabled very efficient stereocontrol.
AB - Synthesis of trichlorinated γ-lactones or γ-lactams from allyl trichloroacetates or N-allyl trichloroacetamides was achieved by transition metal-catalyzed radical cyclizations. Treatment of these trichlorinated starting materials with a catalytic amount of cuprous salts or a ruthenium-phosphine complex resulted in cleavage of a carbon-chlorine bond and subsequent intramolecular addition of the carbon moiety and the chlorine atom to the carbon- carbon double bond. Stereochemistry of the product was similar to that observed in free radical cyclizations ; e.g. stereochemistry of β- and γ-substituents generated by the cyclization of 1-methyl-2-propenyl trichloroacetate was predominantly trans, whereas a cis-fuzed bicyclic lactone was formed by the reaction of 2-cyclohexenyl trichloroacetate. The cyclization of N-allyl trichloroacetamides offers a facile preparative method for pyrrolidinone derivatives from easily available allylic alcohols by the combination with the [3.3] -sigmatropic rearrangement of allyl trichloroimidates. It also provides an interesting entry to alkaloid skeletons. In the cyclization of N-substituted N-allyl trichloroacetamides, judicious choice of the N-substituent and the catalyst dramatically lowered the reaction temperature, and enabled very efficient stereocontrol.
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U2 - 10.5059/yukigoseikyokaishi.53.298
DO - 10.5059/yukigoseikyokaishi.53.298
M3 - Article
AN - SCOPUS:0029280613
VL - 53
SP - 298
EP - 307
JO - Yuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry
JF - Yuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry
SN - 0037-9980
IS - 4
ER -