Phosphine‐Catalyzed Activation of Alkylidenecyclopropanes: Rearrangement to Form Polysubstituted Furans and Dienones

• Published in: Angewandte Chemie International Edition Vol. 58; no. 31; pp. 10698 - 10702
• Main Authors: He, Xin, Tang, Yuhai, Wang, Yongzhuang, Chen, Jian‐Bo, Xu, Silong, Dou, Jianwei, Li, Yang
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 29.07.2019; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Adducts; Allene; Chemistry; Chemistry, Multidisciplinary; dienones; Furans; Intermediates; organocatalysis; Pesticides; Phosphine; phosphines; Physical Sciences; rearrangement; Ring opening; Science & Technology; Substrates; Zwitterions; phosphines; ALPHA,BETA-UNSATURATED IMINES; CYCLOPROPYL KETONES; RING EXPANSION; dienones; ACRYLAMIDE-TETHERED ALKYLIDENECYCLOPROPANES; BAYLIS-HILLMAN ACETATES; 3+2 CYCLOADDITION; organocatalysis; 4+2 ANNULATION; FACILE SYNTHESIS; DELTA-ACETOXY ALLENOATES; furans; STEREOSELECTIVE-SYNTHESIS; rearrangement
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201903320

We report a phosphine‐catalyzed ring opening of electron‐deficient alkylidenecyclopropanes (ACPs) to generate allylic phosphonium zwitterions that resemble the well‐studied phosphine‐allene adducts but exhibit distinct properties. The potent reactivity of these intermediates has been demonstrated in three types of substrate‐controlled phosphine‐catalyzed rearrangements of alkylidenecyclopropylketones, which chemoselectively afford tri‐ and tetrasubstituted furans, and trisubstituted dienones in good yields. One to three: Phosphine‐catalyzed activation of alkylidenecyclopropanes (ACPs) generates allylic phosphonium intermediates that resemble the well‐studied phosphine‐allene adducts but exhibit distinct properties. These intermediates facilitate three types of rearrangements to form polysubstituted furans and dienones.