are the same as those for the gauche rotamer; the methylene protons appear as a singlet at 6 = 4.09). 6 values are in ppm relative to Me4Si.Preparation of (6-Methyl-2-pqridyl)methyllithium. To a hexane solution of n-butyllithium was added 2,6-dimethylpyridine by syringe. The solution was stirred, butane was evolved, and a yellow precipitate formed. This was collected by filtration, dried in vacuo, and stored in sealed ampules.X-ray Structural Determination. A crystal of dimensions 0.05 X 0.24 X 0.30 mm was mounted in a nitrogen-filled glovebag and transferred to the liquid-nitrogen boil-off cooling system of the dif-fra~t0meter.I~ The diffractometer utilized for data collection was designed and constructed locally. A Picker four-circle goniostat equipped with a Furnas Monochromator (HOG crystal) and Picker X-ray generator was interfaced to a TI 980 minicomputer, with Slo-syn stepping motors to drive the angles. Centering was accomplished with use of top/bottom-left/right slit assemblies. The minicomputer is interfaced by low-speed data lines to a CYBER 172-CDC 6600 multimainframe system where all computations are performed.The cell dimensions obtained from 36 reflections at -171 "C with Mo K a (A = 0.71069 A) were a = 22.013 ( 5 ) A, b = 7.974 (2) A, c = 14.933 (3) A, /3 = 96.43 (l)", V = 2604.74 A3, Z = 4, d,,, = 1.480 g. ~m -~, and space group P2,/a. A total number of 6282 reflections were collected by using standard moving-crystal moving-detector techniques with the following values: scan speed = 5" min-', scan width = 1.6 + dispersion, single background time at extremes of scan = 4 s, aperture size = 3.0 X 4.0 mm. (15) J. C. Huffman, Ph.D Thesis, Indiana University, Blwmington, Ind., 1974.The limits of the data collection were 5" < 28 < 50". The number of reflections with F > 2.33u(F) was 3383 of the 4621 unique amplitudes. The data were corrected for absorption (linear absorption coefficient = 9.591 cm-'); minimum and maximum corrections were 0.7980 and 0.9080, respectively.The structure was solved by a combination of direct and Fourier methods to give final residuals RF = 0.0709 and R,F = 0.0560. The goodness of the fit for the last cycle was 1.416, and the maximum 6
