Asymmetric γ-Selective Pentadienylation of Aldehydes Catalyzed by BINAP•Ag(I) Complex

Cobalt-Catalyzed Diastereo- and Enantioselective Allyl Addition to Aldehydes and α-Ketoesters through Allylic C–H Functionalization

“…However, very few enantioselective methods have been developed for addition of a 1,4-diene unit to carbonyls and the diversity of 1,4-diene groups that can be introduced is very limited. 55,56 We next applied the reaction conditions to the transformations of 1,4-dienes ( Figure 4). Unexpectedly, we found that a trisubstituted alkene moiety is required for high e ciency and stereoselectivity.…”

Aldol and Related Processes

“…This silver-BINAP catalyst can be applied for the reaction of 2,4-pentadienylstannane and aldehydes. 5 Generally, the reaction of 2,4-pentadienylstannane and aldehydes in the presence of a Lewis acid catalyst afforded the corresponding e adduct. On the other hand, the reaction using the silver catalyst gave the corresponding g adduct predominantly (Table 9.3).…”

Enantioselective Syntheses of 1,4-Pentadien-3-yl Carbinols via Brønsted Acid Catalysis

“…Enantioenriched 1,4-pentadien-3-yl carbinols (e.g., A and 2 in Scheme ) are important building blocks in organic synthesis. − They are valuable intermediates not only in natural product synthesis but also in the preparation of small-molecule probes for biological evaluations . For instance, compound A , which contains a 1,4-pentadien-3-yl carbinol moiety, underwent a highly diastereoselective intramolecular Pauson–Khand reaction to give ketone B (Scheme a) .…”

“…The Araki and Fallis groups showed that racemic carbinols 2 can also be synthesized via regioselective aldehyde allylation with pentadienyl indium reagents generated from bromo-pentadienes and indium metal. , A Ti-mediated carbonyl addition with pentadienyl titanium reagents was disclosed by the Sato and Schlosser groups independently. , By contrast, very few methods are known to produce enantioenriched 1,4-pentadien-3-yl carbinols 2 , in particular the catalytic asymmetric variants. Yamamoto and co-workers reported a BINAP·Ag­(I) complex-catalyzed asymmetric γ-selective addition to aldehydes with pentadienyl stannanes, and carbinols 2 were obtained with moderate to high enantioselectivities (58–90% ee). However, the toxicity of organotin reagents poses a severe limit on their synthetic utilities on a practical scale.…”

“…3d,e By contrast, very few methods are known to produce enantioenriched 1,4-pentadien-3-yl carbinols 2, in particular the catalytic asymmetric variants. Yamamoto and co-workers reported a BINAP•Ag(I) complex-catalyzed asymmetric γselective addition to aldehydes with pentadienyl stannanes, 4 and carbinols 2 were obtained with moderate to high enantioselectivities (58−90% ee). However, the toxicity of organotin reagents poses a severe limit on their synthetic utilities on a practical scale.…”