Ring-Opening <i>Ortho</i>-C–H Allylation of Benzoic Acids with Vinylcyclopropanes: Merging Catalytic C–H and C–C Activation Concepts
作者:Zhiyong Hu、Xiao-Qiang Hu、Guodong Zhang、Lukas J. Gooßen
DOI:10.1021/acs.orglett.9b02393
日期:2019.9.6
A Ru-catalyzed selective and atom-economic ortho-C-H allylation of aromatic acids with vinylcyclopropanes is reported. The reaction proceeds with selective cleavage of both a C-H and a C-C bond. A wide range of allylarenes were synthesized in high yields and stereoselectivities. The vinylcyclopropane substrates can optionally be generated in situ from a diazo compound and 1,3-butadiene. Concise syntheses
Fragranced compositions and fragranced articles containing an aroma-augmenting or aroma-enhancing amount of a 2,3-dihydrofuran corresponding to the formula ##STR1## wherein R' is an alkyl group having from 1 to 4 carbon atoms, R** is an alkyl group having from 1 to 5 carbon atoms, R.sub.1 is an alkyl group having from 1 to 4 carbon atoms, R.sub.2 is hydrogen or an alkyl group having from 1 to 6 carbon atoms, and R.sub.3 and R.sub.4 are hydrogen or a methyl group, and a process for obtaining same are provided.
2,4,5-Trisubstituted-2,3-dihydrofurans useful as fragrance compounds are provided herein. The compounds of this invention correspond to the general formula ##STR1## wherein R is an ethyl or vinyl group, R.sub.1 is an alkyl group having from 1 to 4 carbon atoms and R.sub.2 is a hydrocarbon radical having from 3 to 10 carbon atoms. The 2,3-dihydrofuran compounds of the present invention are useful components in the preparation and formulation of fragranced cosmetic and toiletry products.
2,3-Dihydrofurans having highly desirable odor characteristics closely mimicking that of natural products are provided herein. The 2,3-dihydrofurans correspond to the formula ##STR1## wherein R' is an alkyl group having from 1 to 4 carbon atoms, R** is an alkyl group having from 1 to 5 carbon atoms, R.sub.1 is an alkyl group having from 1 to 4 carbon atoms, R.sub.2 is hydrogen or an alkyl group having from 1 to 6 carbon atoms, and R.sub.3 and R.sub.4 are hydrogen or a methyl group. The 2,3-dihydrofuran compounds are useful in the preparation of fragrance compositions and fragranced articles and can be employed in conjunction with known fragrance materials to augment or enhance the aromas thereof.
Sulfoxonium ylide chelation-assisted C–H allylation of arenes has been accomplished utilizing strained vinyl carbo/heterocycles as the allyl surrogates via sequential C–H and C–C/het bond activation. Broad substrate scope, Co-catalysis, selectivity, and late-stage drug mutation are the important practical features.