Rh(III)-catalyzed [3 + 2] spiroannulation of 2,3-dihydro-1,4-benzoxazines with 4-hydroxy-2-alkynoates through ortho-C-H bond functionalization

Kommu Nagesh; Jagadish Manda; B Sridhar; B V Subba Reddy

doi:10.1039/d3ob00786c

Rh(III)-catalyzed [3 + 2] spiroannulation of 2,3-dihydro-1,4-benzoxazines with 4-hydroxy-2-alkynoates through ortho-C-H bond functionalization

Org Biomol Chem. 2023 Aug 2;21(30):6169-6173. doi: 10.1039/d3ob00786c.

Authors

Kommu Nagesh^{1

2}, Jagadish Manda^{1

2}, B Sridhar³, B V Subba Reddy^{1

2}

Affiliations

¹ Fluoro-Agrochemicals, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India. basireddy@iict.res.in.
² Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India.
³ Laboratory of X-ray Crystallography, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India.

PMID: 37464919
DOI: 10.1039/d3ob00786c

Abstract

Rhodium(III)-catalyzed [3 + 2]-spiroannulation of 2-aryl-1,4-benzoxazines with 4-hydroxy-2-alkynoates has been developed for the synthesis of highly rigid spirolactones in good yields with high regioselectivity. The reaction proceeds through a cascade of C-H activation followed by C-H annulation and lactonization. In this approach, two C-C and C-O bonds are formed in a single step. This is the first report on the spiroannulation of 2,3-dihydro-1,4-benzoxazines with 4-hydroxy-2-alkynoates.