溴甲基甲基醚 、 1-[(3'R,6'S)-1'-benzyl-3',6'-dihydro-5'-ethoxy-6'-isopropylpyrazin-3'-yl-2'-one]-3-[(3''R,6''S)-1''-benzyl-3'',6''-dihydro-5''-ethoxy-6''-isopropylpyrazin-3''-yl-2''-one]-2-methylenepropane 在
lithium hexamethyldisilazane 作用下,
以
四氢呋喃 为溶剂,
以85%的产率得到(3R,6S)-1-Benzyl-3-[2-((2R,5S)-4-benzyl-6-ethoxy-5-isopropyl-3-oxo-2,3,4,5-tetrahydro-pyrazin-2-ylmethyl)-allyl]-5-ethoxy-6-isopropyl-3-methoxymethyl-3,6-dihydro-1H-pyrazin-2-one