Addition of 2-(chloromagnesiomethyl)2-alkenyl ethers to epoxides followed by Pd(0)-catalyzed cyclization: a one-pot synthesis of 3-methylenetetrahydropyrans
摘要:
Addition of 2-(chloromagnesiomethyl)-2-propenyl ethers 1a and 1b to epoxides 3 affords ring opening products 6 or 7 which are converted by Pd(0) to 3-methylenetetrahydropyrans 9. Cyclization of the addition products is best effected by a catalyst system generated in situ from Pd(OAc)2 and (i-PrO)3P.