The reaction of triarylantimony diacetates [Ar3Sb(OAc)2] with dialkyl H-phosphites [H-PO(OR)2] in the presence of a Pd(PPh3)4 (5 mol%) catalyst led to the formation of arylphosphonates in moderate to excellent yield under base-free conditions. This reaction is the first example of carbon-phosphorus bond formation by using an organoantimony compound as a pseudo-halide.

Normal mode calculations have been done on 92 disulfide bridges in 25 known protein structures in order to correlate the SS stretch frequency with the CCSS dihedral angle. It is possible to classify the frequencies into four major categories, which provide a more detailed classification scheme than previously proposed from dialkyl disulfide correlations.

We report here that polysubstituted dihydroisoquinolones and isoquinolones can be constructed by the one-pot reaction of the readily available acyclic α,β-unsaturated carbonyl precursors and dialkyl glutaconates under mild basic conditions (1-45 min for the former vs. 1-6 h for the latter) via the domino process involving [3+3] annulation/intramolecular aza-cyclization.

The title compound, C(26)H(38)O(3), was prepared by an intra-molecular Claisen-like cyclization of ethyl 2-acet-oxy-4,4-dimethyl-1-(3-methyl-but-2-en-yl)cyclo-hex-2-enecarboxyl-ate followed by dialkyl-ation. One of the methyl groups is disordered over two sets of sites in a 0.67:0.33 ratio.

4-aroyl-5-aryl-2,3-furandiones and N,N-dialkyl urea combine with loss of water yielding the pyrrole2,3-dione derivatives in moderate yields (47-68%). Then, these compounds were converted into 2(1H)quinoxalinones with various 1,2-phenylenediamines. The structures and characterizations of the synthesized compounds were established by the Hand C-NMR, IR and elemental analysis.

The title compound, C(22)H(20)ClN(3), is composed of a dialkyl-substituted pyrazole ring connected to an aryl-substituted isoquinoline ring system with a dihedral angle of 55.8 (1)° between the pyrazole ring and and the isoquinoline ring system. The dihedral angle between the chloro-phenyl ring and the isoquinoline ring system is 28.3 (1)°.

Addition of anions derived from dialkyl methylphosphonates to (Ss)-N-tert-butanesulfinyl (3,3,3)-trifluoroacetaldimine afforded (Ss,R) addition adducts in moderate to good yield (53-75%) with excellent diastereoselectivity (94-95% de). After selective removal of the N-sulfinyl group, dipeptides containing enantiomerically pure diethyl 2-amino-3,3,3-trifluoropropylphosphonate were synthesized to...