Y(OTf)3-catalyzed phosphorylation of 2H-chromene hemiacetals with P(O)-H compounds to 2-phosphorylated 2H-chromenes.

A facile synthesis of 2-phosphorylated 2H-chromenes has been accomplished herein via a Y(OTf)3-catalyzed dehydrative coupling of 2H-chromene hemiacetals with P(O)-H compounds. This protocol features low catalyst loading, mild reaction conditions, broad substrate scope and easy elaboration of the products.

Recent progress in the synthesis of phosphorus-containing indole derivatives.

Phosphorus-containing indole derivatives represent a special class of phosphorus-containing nitrogen heterocycles, which not only widely exist in pharmaceutical agents, but also have widespread applications in materials science and organic synthesis as ligands and intermediates. The synthesis of such compounds is of current interest, with two major synthetic strategies being established. This review summarizes the recent progress in this field, including the advantages and limitations of each subdivisional tactic, briefly discusses the reaction mechanisms and challenges, and outlines the synthetic opportunities still open.

A highly efficient nucleophilic substitution reaction between R2P(O)H and triarylmethanols to synthesize phosphorus-substituted triarylmethanes.

A highly efficient and general nucleophilic substitution reaction between dialkyl H-phosphonates or diarylphosphine oxides and triarylmethanols catalyzed by HOTf (trifluoromethanesulfonic acid) has been developed. It provides an atom-economical protocol for the synthesis of various symmetrical and unsymmetrical phosphorus-substituted triarylmethanes that constitute an emerging family of potent anticancer agents in rich diversity with 40 to 96% yields. The synthetic applicability of this protocol is demonstrated by gram-scale preparations.

Brønsted acid-catalysed regiodivergent phosphorylation of 2-indolylmethanols to synthesize benzylic site or C3-phosphorylated indole derivatives.

A Brønsted acid catalysed regiodivergent phosphorylation of 2-indolylmethanols with diarylphosphine oxides has been established, which provides a brand-new strategy for accessing highly functionalized phosphorus-containing indoles with structural diversity. Under the catalysis of HOTs·H2O, 2-indolylmethanols undergo regioselective benzylic phosphorylation at room temperature to afford benzylic site phosphorylated indoles in good to high yields (29 examples, up to 98% yield), while C3-phosphorylated indoles are obtained in the presence of HOTf under heating conditions (16 examples, up to 83% yield). Preliminary mechanistic studies suggest that C3-phosphorylated indoles are possibly obtained partially from direct C3-phosphorylation and dominantly from a tandem benzylic phosphorylation/[1,3]-P migration/isomerization sequence from 2-indolylmethanols. Furthermore, the acidity of the Brønsted acid and the reaction temperature play a vital role in the [1,3]-P migration of benzylic phosphorylated indoles to form C3-phosphorylated indoles. This protocol serves as a good example for regioselective benzylic functionalization of 2-indolylmethanols.