Antiviral effects of three novel derivatives of adefovir on the replication of hepatitis B virus

In(III)-Catalyzed 1,2-Hydrophosphorylation of 3-Alkynyl-3-hydroxyisoindolinones to 3,3-Disubstituted Isoindolinones Featuring Both Phosphoryl and Alkynyl Groups at the C3-Position

We report a highly regioselective 1,2-addition of P(O)-H compounds to the in situ generated β,γ-alkynyl-α-ketimine derived from 3-alkynyl-3-hydroxyisoindolinones, which provided a general protocol for the preparation of 3,3-disubstituted isoindolinones featuring both phosphoryl and alkynyl groups at a quaternary carbon center. The use of only 2-5 mol % of an inexpensive catalyst (In(ClO4)3·8H2O or Bi(OTf)3) allowed the smooth output of the desired products under mild conditions (25 °C, 0.5-24 h) with a broad substrate scope (35 examples) in up to >99% yield. The obtained products could be further elaborated based on the alkyne moiety. The initial asymmetric trial indicated that the use of BINOL-derived CPA could enable an enantioselective induction in up to a 46% yield with 77% ee.

Pd(0)-Catalyzed Cyclizative Phosphorylation of (Z)-1-Iodo-1,6-diene: Synthesis of Alkylphosphonate and Alkylthionophosphonate

A palladium-catalyzed cyclizative phosphorylation reaction of (Z)-1-iodo-1,6-diene with diethyl H-phosphonate is developed, which provides facile access to unsaturated six-membered heterocycles bearing an alkylphosphonate group. The key step of this process is the efficient capture of the involved alkyl-Pd(II) species by H-phosphonate with the help of CsF, followed by reductive elimination of alkyl-Pd(II)-P(O)(OEt)₂. Moreover, this reaction is successfully extended to H-thionophosphonate.

Direct Synthesis of Phosphonates and α-Amino-phosphonates from 1,3-Benzoxazines

A straightforward and novel method for transformation of readily available 1,3-benzoxazines to secondary phosphonates and α-aminophosphonates using boron trifluoride etherate as catalyst is developed. The formation of phosphonates proceeds through ortho-quinone methide (o-QM) generated in situ, followed by a phospha-Michael addition reaction. On the other hand, the α-aminophosphonates were obtained by iminium ion formation and the subsequence nucleophilic substitution of alkylphosphites. This method can be also used for the preparation of o-hydroxybenzyl ethers through oxa-Michael addition.

Palladium-Catalyzed Benzylic Phosphorylation of Diarylmethyl Carbonates

A palladium-catalyzed benzylic substitution of tert-butyl diarylmethyl carbonates with a pinacol-derived H-phosphonate proceeds to deliver the corresponding benzylic phosphorylated products in good yields. Moreover, the asymmetric synthesis is possible via a Pd/( R_p, R'_p)-( S)-Mandyphos-catalyzed kinetic resolution-DYKAT (dynamic kinetic asymmetric transformation) sequence, and optically active α-chiral diarylmethylphosphonates are obtained with synthetically useful yields and enantiomeric ratios (up to 50% and 92:8 er).

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

A highly efficient nucleophilic substitution reaction between R₂P(O)H and triarylmethanols was reported, which provides phosphorus-substituted triarylmethanes in rich diversity with 40–96% yields.

Recent progress in the synthesis of phosphorus-containing indole derivatives

Phosphorus-containing indole derivatives represent a special class of phosphorus-containing nitrogen heterocycles. This review summarizes the recent progress in the synthesis of such compounds, briefly discusses the reaction mechanisms and challenges, and outlines the synthetic opportunities still open.

First DMAP-mediated direct conversion of Morita-Baylis-Hillman alcohols into γ-ketoallylphosphonates: Synthesis of γ-aminoallylphosphonates

An efficient synthesis of a series of γ-ketoallylphosphonates through a direct conversion of both primary and secondary Morita–Baylis–Hillman (MBH) alcohols by trialkyl phosphites with or without DMAP, used as additive, and under solvent-free conditions, is described herein for the first time. Subsequently, a highly regioselective Luche reduction of the primary phosphonate 2a (R = H) gave the corresponding γ-hydroxyallylphosphonate 5 that further reacted with tosylamines in the presence of diiodine (15 mol %) as a catalyst, affording the corresponding S_N2-type products 6a–d in 63 to 70% isolated yields. Alternatively, the alcohol 5 produced the corresponding acetate 7 which, mediated by Ce(III), was successfully converted into the corresponding γ-aminoallylphosphonates 8a–d.

Exceptional effect of nitro substituent on the phosphonation of imines: the first report on phosphonation of imines to α-iminophosphonates and α-(N-phosphorylamino)phosphonates

A novel chemoselective method for the simple phosphonation of imines withH-phosphonate diethyl ester and study of the electronic and orientation effects of the substituents on phosphorylation reaction.

Palladium-catalyzed α-arylation of benzylic phosphonates

A new synthetic route to access diarylmethyl phosphonates is presented. The transformation enables the introduction of aromatic groups on benzylic phosphonates via a deprotonative cross-coupling process (DCCP). The Pd(OAc)2/CataCXium A-based catalyst afforded a reaction between benzyl diisopropyl phosphonate derivatives and aryl bromides in good to excellent isolated yields (64-92%).