Recent work on state sum models of quantum gravity in 3 and 4 dimensions has led to interest in the ‘quantum tetrahedron’. Starting with a classical phase space whose points correspond to geometries of the tetrahedron in R3, we use geometric quantization to obtain a Hilbert space of states. This Hilbert space has a basis of states labeled by the areas of the faces of the tetrahedron together wi...

High yielding synthetic routes to 3’,5’-diamino-2’,3’,5’-trideoxycytidine and 3’,5’-diamino-2’,3’,5’-trideoxyadenosine are described. In addition, the protonation behavior of 3’,5’-diamino-2’,3’,5’-trideoxycytidine, 3’,5’-diamino-2’,3’,5’-trideoxyadenosine, 3’,5’diamino-3’,5’-dideoxythymidine, and 3’,5’-diamino-2’,3’,5’-trideoxyuridine has been studied by means of pH-metric measurements and NMR...

Recent work on state sum models of quantum gravity in 3 and 4 dimensions has led to interest in the ‘quantum tetrahedron’. Starting with a classical phase space whose points correspond to geometries of the tetrahedron in R3, we use geometric quantization to obtain a Hilbert space of states. This Hilbert space has a basis of states labeled by the areas of the faces of the tetrahedron together wi...

Recent work on state sum models of quantum gravity in 3 and 4 dimensions has led to interest in thèquantum tetrahedron'. Starting with a classical phase space whose points correspond to geometries of the tetrahedron in R 3 , we use geometric quantization to obtain a Hilbert space of states. This Hilbert space has a basis of states labeled by the areas of the faces of the tetrahedron together wi...

reaction of dialkyl acetylenedicarboxylates 1a-c andpyrrole derivatives 2a-e in the presence of triphenylphosphite (tpp) was investigated and the effect of the pyrrole substitution was established. diastereoselectivity is observed with pyrroles, 2a,b, yieldingphosphonate ester derivatives 3a-f and 4,and their relative configuration is determined by 1h/13c and 31p nmr and confirmed by single x-r...

Since its discovery the rearrangement of R-metalated ethers, particularly the [2,3]-Wittig rearrangement, has been the subject of intensive mechanistic and synthetic investigations.1 Relative to the [2,3]-shift, the [1,2]-Wittig rearrangement has received relatively little publicity. Most studies of the [1,2]-Wittig have been mechanistic in origin, resulting in the widely accepted theory that t...