Indium(i)-catalyzed alkyl–allyl coupling between ethers and an allylborane

Abstract

An efficient method for alkyl-allyl cross-coupling between ethers and a 9-BBN-derived allylborane catalyzed by indium(I) triflate has been developed. The allylborane proved to be essential to obtain the desired products in high yields. The reaction displayed good substrate scope including high functional group tolerance.

“Design” of Boron‐Based Compounds as Pro‐Nucleophiles and Co‐Catalysts for Indium(I)‐Catalyzed Allyl Transfer to Various Csp3‐Type Electrophiles

“…Our work not only represents a significant advance compared with our earlier studies in terms of scope, [6,7] but also sheds further light on the involved reaction mechanism. Our work not only represents a significant advance compared with our earlier studies in terms of scope, [6,7] but also sheds further light on the involved reaction mechanism.…”

“…Scope and limitation for the InOTf-catalyzed allylation of ethers 1 with 2 b are shown in Table 3. [7] We have proposed a transmetalative S N 1 mechanism, in which indium(I) plays a dual role, as shown in Figure 1. [7] We have proposed a transmetalative S N 1 mechanism, in which indium(I) plays a dual role, as shown in Figure 1.…”

“…The present catalytic alkyl-allyl cross-coupling showed good substrate generality including various primary, secondary, and tertiary benzylic, allylic, and propargylic ethers, thereby providing the corresponding allylated products in good to excellent yields in most cases. [7] First, InOTf acts as a Lewis acid to activate the C À O bond, thereby forming a carbenium ion species A (an oxocarbenium ion species in the case of acetals) and indium(I) methoxide. [7] First, InOTf acts as a Lewis acid to activate the C À O bond, thereby forming a carbenium ion species A (an oxocarbenium ion species in the case of acetals) and indium(I) methoxide.…”

“…[7] Our present contribution provides a full account on issues relat-Abstract: We have recently uncovered a general indium(I)-catalyzed method for allylations and propargylation of acetals and ketals with a water-and air-stable allyl boronate. [7] Our present contribution provides a full account on issues relat-Abstract: We have recently uncovered a general indium(I)-catalyzed method for allylations and propargylation of acetals and ketals with a water-and air-stable allyl boronate.…”

Gallium and Indium Compounds in Homogeneous Catalysis

“…(72). 100 The reaction proceeds through a transmetalative S N 1 and first involves an In(I)-mediated C-O bond cleavage of the ether moiety to form a carbocation and InOMe. Transmetalation with allylborane may afford the corresponding In(I) allyl species that may then react with the formed carbocation to yield the final product.…”