Regioselective coupling of allylic ethers with ethyl 2-trimethylsilyl-3-butenoate

In the presence of TiCl₄ the 4 position of the title silyl ester reacts with such electrophiles as allylic ethers or bromides carrying the leaving group on the secondary carbon without allylic rearrangement.     

Search for a Ks0π±π+π− resonance near 2.6 GeV in 14.75 GeV/ c pp interactions

We present the results of a search for a resonance at 2.6 GeV decaying into K_S⁰π^±π⁺π^? in the six-prong plus K_S⁰ final state in 14.75 GeV/c$\text{p}\text{p}$ interactions. We do not find confirming evidence, and with 95% confidence we quote an upper limit of σ·BR < 21 ub.     

Reformatsky type reaction by means of Bu3SnA1et2 or Bu3Pba1et2

Treatment of α-halo carbonyl compounds with title Sn-Al or Pb-Al reagents provides enolates which react with aldehydes or ketones to give β-hydroxy carbonyl compounds effectively.     

Heavily carbon-doped p-type InGaAs by MOMBE

Carbon-doped In_xGa_1−xAs layers (x=0−0.96) were grown by metalorganic molecular beam epitaxy (MOMBE) using trimethylgallium (TMG), solid arsenic (As₄) and solid indium (In) as sources of Ga, As and In, respectively. The carrier concentration is strongly affected by growth temperature and indium beam flux. Heavy p-type doping is obtained for smaller In compositions. The hole concentration decreases with the indium composition from 0 to 0.8, and then the conductivity type changes from p to n at x=0.8. Hole concentrations of 1.0×10¹⁹ and 1.2×10¹⁸ cm^-3 are obtained for x=0.3 and 0.54, respectively. These values are significantly higher than those reported on carbon-doped In_xGa_1−xAs by MBE. Preliminary results on carbon-doped GaAs/In_xGa_1−xAs strained layer superlattices are also discussed.