Lewis Acid Catalyzed Stereoselective Dearomative Coupling of Indolylboron Ate Complexes with Donor–Acceptor Cyclopropanes and Alkyl Halides

Abstract

Indolylboron ate complexes readily generated from 2-lithioindoles and boronic esters underwent multicomponent dearomative coupling with D-A cyclopropanes and alkyl halides in the presence of Sc(OTf) 3 as acatalyst. The reactions proceeded with complete diastereoselectivity and excellent stereospecificity to providei ndolines containing three contiguous stereocenters.The valuable boronic ester moiety remains in the product and allows for subsequent functionalization.

A Widely Applicable and Versatile Method for the Ring‐Opening 1,3‐Carbocarbonation of Donor‐Acceptor Cyclopropanes

“…Even less explored is the field of 1,3‐dicarbofunctionalizations. The Studer group employed indoylboron ate complexes, and coupled these with DACs and alkyl halides [13] . Saha et al.…”

Divergent Copper‐salt‐controlled Reactions of Donor‐Acceptor Cyclopropanes and N‐Fluorobenzene Sulfonimide: Access to the 1,3‐Haloamines and Aminoindanes

“…reported methods for 1,3‐chlorothioetherification or 1,3‐dichlorination of D‐A cyclopropanes with RSCl/MgI 2 or PhICl 2 , respectively (Scheme 1a) [5c,d] . Arbeit and coworkers also developed a method for 1,3‐carboamination of D‐A cyclopropanes in the presence of 1,3,5‐triaryltriazinane [5e] . Despite the above‐described advances, the utility of these reactions is limited by the need to use highly reactive substrates or catalysts.…”