Rhodium-Catalyzed Oxidative Cyclization of Arylphosphonic Acid Monoethyl Esters with Alkenes: Efficient Synthesis of Benzoxaphosphole 1-Oxides

Abstract

Rhodium-catalyzed tandem oxidative alkenylation and an intramolecular oxy-Michael reaction were developed using arylphosphonic acid monoethyl esters and alkenes under aerobic conditions, which produced benzoxaphosphole 1-oxides in good to excellent yields.

Phosphaannulation of Aryl‐ and Benzylphosphonic Acids with Unactivated Alkenes via Palladium‐Catalyzed CH Activation/Oxidative Cyclization Reaction

“…Accordingly, we recently developed synthetic approaches to cyclic phosphonates via phosphoryl group‐directed CH activation: Rh‐catalyzed activation/Michael reaction using phosphonic acids and activated alkenes [Eq. (1), Scheme ],7 Pd‐catalyzed CH activation/cyclization of aryl‐ and benzylphosphonic acids [Eq. (2)],8 and Rh‐ or Ru‐catalyzed CH activation/annulations using phosphonic acids and disubstituted alkynes [Eq.…”

Rh‐Catalyzed Synthesis of Oxygen‐Containing Heterocycles

“…The carbonyl group also plays a key role in this reaction because no desired products were detected when imines were subjected to the standard reaction conditions (Scheme 6.8c). In the same year, a rhodium(III)-catalyzed cyclization by employing alkenes and arylphosphonic acid monoesters for the synthesis of benzoxaphosphole 1-oxides was reported by Lee and coworkers (Scheme 6.9) [17]. Using the combination of [RhCp*Cl 2 ] 2 as the catalyst and CH 3 CN as the solvent, the cyclization showed broad scope to both internal alkynes and arylphosphonic acid monoesters.…”

Fifty Years of (Benz)oxaphospholene Chemistry

“…[127] They found that these compounds reactedw ith electron-deficient alkenesi nt he presence of aR h-catalyst, an oxidant (AgOAc) andabase (LiOAc), producing two products in an almoste quimolar ratio:a lkenyl product 156 and benzoxaphosphole 157.I ti sc lear that benzoxaphosphole 157 results from intramolecular oxa-Michael addition of 156.B ase and solvent screening led to optimized conditions in which only the desired benzoxaphospholene 157 was produced in 85 %i solated yield. [127] They found that these compounds reactedw ith electron-deficient alkenesi nt he presence of aR h-catalyst, an oxidant (AgOAc) andabase (LiOAc), producing two products in an almoste quimolar ratio:a lkenyl product 156 and benzoxaphosphole 157.I ti sc lear that benzoxaphosphole 157 results from intramolecular oxa-Michael addition of 156.B ase and solvent screening led to optimized conditions in which only the desired benzoxaphospholene 157 was produced in 85 %i solated yield.…”

“…In 2013, the group of Lee reported on the CÀHa ctivation of o-tolylphosphonic acid monoethyl esters 155 (Scheme 38). [127] They found that these compounds reactedw ith electron-deficient alkenesi nt he presence of aR h-catalyst, an oxidant (AgOAc) andabase (LiOAc), producing two products in an almoste quimolar ratio:a lkenyl product 156 and benzoxaphosphole 157.I ti sc lear that benzoxaphosphole 157 results from intramolecular oxa-Michael addition of 156.B ase and solvent screening led to optimized conditions in which only the desired benzoxaphospholene 157 was produced in 85 %i solated yield. Substrate scope determination revealed that av ariety of electron-deficient alkenes readily reacted to give the benzoxaphospholenes 157 in high yields.…”

“…In 2013, the group of Lee reported on the C−H activation of o ‐tolylphosphonic acid monoethyl esters 155 (Scheme ) . They found that these compounds reacted with electron‐deficient alkenes in the presence of a Rh‐catalyst, an oxidant (AgOAc) and a base (LiOAc), producing two products in an almost equimolar ratio: alkenyl product 156 and benzoxaphosphole 157 .…”