A novel mild methodology for the preparation of o-hydroxybenzyl ketones is described starting from o-alkenyl phenols and based on the VO(acac)(2)/TBHP (2 mol %/1.2 equiv) system. VO(acac)(2) first catalyzes the epoxidation of o-alkenyl phenols and then the rearrangement of the epoxyphenols to ketones via the selective benzylic C-O cleavage and 1,2 hydride migration. The protocol has also been applied to set up a useful and easy one-pot conversion of o-alkenyl phenols to benzo[b]furans by means of the sequential addition of TFA, after the generation of the intermediate o-hydroxybenzyl ketones.
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http://dx.doi.org/10.1021/jo026783j | DOI Listing |
Chemistry
December 2023
Department of Organic Synthesis & Process Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500 007, India.
Although challenging, the distant C-H functionalization with precision is quite rewarding and has long been intriguing. Tailoring an appropriate template accomplishes the job but the prerequisite sets the limitation. We herein unveil our discovery of annulation of alkynes on to two distant (from directing group) C-H bonds through rollover cyclometallation assisted by conjugated C=C bond.
View Article and Find Full Text PDFOrg Lett
July 2022
Department of Organic Synthesis & Process Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad 500007, India.
We disclose herein a Rh(III)-catalyzed migratory three-point double annulation of -alkenyl phenols with propargyl alcohols for de novo construction of naphtho furan derivatives in a regio- and chemoselective manner. The protocol orchestrates two new rings with four new bonds in one operation without the need for any additive. Necessary labeled and control experiments are conducted to elucidate the reaction mechanism.
View Article and Find Full Text PDFJ Org Chem
February 2014
Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
An efficient Pd(II)-catalyzed oxidative olefination of phenols bearing removable directing groups with molecular oxygen as the sole oxidant has been developed. This reaction protocol provides an efficient and robust synthetic tool for the synthesis of o-alkenyl phenols under mild conditions.
View Article and Find Full Text PDFJ Org Chem
May 2003
Dipartimento di Chimica, Universita' di Salerno, Via S. Allende, I- 84081, Baronissi, Salerno, Italy.
A novel mild methodology for the preparation of o-hydroxybenzyl ketones is described starting from o-alkenyl phenols and based on the VO(acac)(2)/TBHP (2 mol %/1.2 equiv) system. VO(acac)(2) first catalyzes the epoxidation of o-alkenyl phenols and then the rearrangement of the epoxyphenols to ketones via the selective benzylic C-O cleavage and 1,2 hydride migration.
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