Tandem O–H Insertion/[3,3]‐Sigmatropic Rearrangement of Rhodium Carbenoids with 2‐Furfuryl Alcohols: A Strategy To Access Polysubstituted Furans

Abstract

Polysubstituted furans are versatile building blocks in organic synthesis and are widely spread in a variety of natural products, pharmaceuticals, and functional materials. Herein, we report a convenient, facile, and economic approach for the synthesis of polysubstituted furans through a tandem O–H insertion/[3,3]‐sigmatropic rearrangement of rhodium carbenoids with easily available furfuryl alcohols. This protocol is characterized by its operational simplicity, high efficiency with excellent yields, broad substrate scope, and great functional‐group tolerance.

Tandem Insertion–[1,3]‐Rearrangement: Highly Enantioselective Construction of α‐Aminoketones

“…We were pleased to find that thiophen‐2‐ylmethanol ( 3 co , 40 % yield, 86 % ee ) and (1 H ‐indol‐3‐yl) methanol ( 3 cp , 51 % yield, 60 % ee ) were also compatible in such transformation. Interestingly, furan‐2‐ylmethanol was described to undergo a tandem O−H insertion–[3,3]‐sigmatropic rearrangement with rhodium salt . However, under current dual catalysis, O−H insertion–[1,3] O‐to‐C rearrangement took place and moderate results were afforded (Table , entry 17).…”

1,2,3-Triazole and Its Analogues: New Surrogates for Diazo Compounds

“…Bi and co-workers 211 Zhao and Song reported a convenient approach for the synthesis of polysubstituted furans from furfuryl alcohols and Nsulfonyl triazoles through insertion of the α-imino rhodium carbene into the O−H bond of the furfuryl alcohol followed by [3,3]-sigmatropic rearrangement (Scheme 128). 212 Volla and co-workers 213 diverse tricyclic 2-imidazolones 135.3 in moderate to good yields with excellent diastereoselectivity (Scheme 135). 219 The reaction proceeds through the initial formation of intermediate 225 The formation of the aldol product could be explained in terms of the formation of enolate 141.2 in the presence of Rh 2 (OPiv) 4 and its subsequent reaction with the aldehyde via six-membered transition state 141.3.…”

Dual Role of N‐Bromosuccinimide as Oxidant and Succinimide Surrogate in Domino One‐Pot Oxidative Amination of Benzyl Alcohols for the Synthesis of α–Imido Ketones

“…Traditionally, α‐amino ketones can be synthesized from ketone and amine using molecular bromine . In addition to this, recent developments have been made for the synthesis of α‐amino ketones by using both transition‐metal and transition metal‐free conditions . For example, MacMillan et al developed a Cu‐catalyzed α‐amination of ketones .…”