反应详情

Reaction of the auxiliary (5) (0.180 g, 1.40 mmol) in solution in tetrahydrofuran (3 ml) at -78° C. with butyllithium (1.4M, 1 ml, 1.41 mmol) and pivaloyl chloride (0.190 ml, 1.55 mmol) for 30 minutes and then at room temperature for 1 hour with work-up and recrystallisation at ca -10° C. from 60-80 petroleum ether furnished the title compound (16) as a solid (0.276 g, 93%); νmax (CH2Cl2) 1683 and 1775 cm-1 ; [α]D24 (c 1 in CHCl3)=+51.3; (Found: C, 62.25; H, 9.09; N, 6.45. C11H19NO3 requires C, 61.95; H, 8.98; N, 6.57%); δH (CDCl3 ; 300 MHz) 1.20 (3H, d, J=6.5, CH3CH), 1.31 (9H, s, C(CH3)3), 1.33 (3H, s, C(CH3)2), 1.37 (3H, s, C(CH3)2), 4.11 (1H, q, J=6.5, CHCH3) ; δC (125 MHz; CDCl3) 14.33 (CH3), 21.41 (CH3), 26.31 (CH3), 27.22 (CH3), 41.60 (CH3), 60.92 (CH), 81.01 (C), 151.75 (CO), 179.08 (CO); m/z (CI+, NH3) 214 (M+ +1).

1. customat room temperature for 1 hour with work-up and recrystallisation at ca -10° C. from 60-80 petroleum ether