The (4+1)-annulation of dimethoxycarbene with readily accessible α,β-unsaturated carbonyls gives cyclic orthoesters, which can then be converted in just a few steps to other O-heterocycles, including methoxyfurans, furanones, and furans.
二甲氧基卡宾与容易获得的α,β-不饱和羰基的(4 + 1)环化生成环状原酸酯,然后可以仅几步将其转化为其他O杂环,包括甲氧基
呋喃,
呋喃酮和
呋喃。