Four allylic dioxolanes were prepared and reacted with several dienes in the presence of Lewis acids, affording [4+3] cycloadducts. The reaction could be conducted with catalytic amounts of Lewis acid. The use of a chiral Lewis acid gave a cycloadduct with only a low enantiomeric excess. (c) 2006 Elsevier Ltd. All rights reserved.
Heteroatom-stabilized allylic cations in 4+3 cycloadditions. A tandem Peterson olefination/4+3 cycloaddition reaction
作者:Michael Harmata、Darin E. Jones
DOI:10.1016/s0040-4039(97)00775-2
日期:1997.6
The readily available tertiary alcohols 4a-c react with selected dienes in the presence of titanium tetrachloride to give 4+3 cycloaddition products. The process is best rationalized as a Peterson olefination followed by allylic cation formation and 4+3 cycloaddition. (C) 1997 Elsevier Science Ltd.
Chiral cations in 4+3 cycloadditions
作者:Michael Harmata、Darin E. Jones、Mehmet Kahraman、Uday Sharma、Charles L. Barnes
DOI:10.1016/s0040-4039(99)00080-5
日期:1999.3
The reaction of the chiral acetal 4 with furan and cyclopentadiene in the presence of a Lewis acid gives 4+3 cycloadducts in very good yields. Diastereoselectivity in the case of furan is exceptionally high, while that for the reaction with cyclopentadiene is lower. The sense of diastereoselection in the case of furan is opposite to that which would be predicted on the basis of mechanistic models for the origin of stereoselectivity in many reactions of chiral acetals mediated by Lewis acids. (C) 1999 Elsevier Science Ltd. All rights reserved.
Vinyl Oxocarbenium Ions in Intermolecular [4 + 3] Cycloaddition Reactions
作者:Michael Harmata、Darin E. Jones
DOI:10.1021/jo962374+
日期:1997.3.1
[4+3] Cycloadditions of some allylic dioxolanes
作者:Michael Harmata、James A. Brackley、Charles L. Barnes
DOI:10.1016/j.tetlet.2006.09.036
日期:2006.11
Four allylic dioxolanes were prepared and reacted with several dienes in the presence of Lewis acids, affording [4+3] cycloadducts. The reaction could be conducted with catalytic amounts of Lewis acid. The use of a chiral Lewis acid gave a cycloadduct with only a low enantiomeric excess. (c) 2006 Elsevier Ltd. All rights reserved.