| Summary: | The first diastereodivergent formal [4 + 1] cycloaddition reactions of azoalkenes with p-quinone methides (p-QMs) have been accomplished. The reported reaction occurred via a domino oxa-1,4-addition/1,6-addition process, allowing the use of common azoalkenes as C1 synthons. A broad range of 2,3-dihydrobenzofurans was smoothly prepared in good yields and with reversible diastereoselectivities. The steric hindrance and hydrogen-bonding interaction were proposed to account for the two different modes of diastereo-control. The projected reaction features the employment of azoalkene as carbene-like C1 synthon, mild conditions, broad substrate scope and tunable diastereoselectivity.
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