Dienyl Homoallyl Alcohols via Palladium Catalyzed Ene-Type Reaction of Aldehydes with 1,3-Dienes

Abstract

The combination of Pd catalyst and Xantphos ligand in the presence of Et(3)B nicely promotes the allylation of aldehydes with conjugated dienes to provide dienyl homoallyl alcohols in excellent yields. The reaction occurs selectively at the C-C double bond bearing higher electron density.

The Synthesis of Ipsenol and Ipsdienol: A Review (1968–2020)

“…found a very smart solution by using Pd/Et 3 B catalyzed ene‐type reaction of 3‐methylbutanal with isoprene (Scheme 22). [64] Older and first “isoprene synthons” were based on the organozinc species III (Scheme 1, Figure 3), prepared from 1,4‐dibromo‐2‐(bromomethyl)but‐2‐ene ( 1 ) [1] or from 2‐(bromomethyl)buta‐1,3‐diene ( 2 ), [1,14,27] that gave the desired compounds in modest yields, but from cheap and easily available starting materials. (2‐Methylenebut‐3‐en‐1‐yl)potassium species IV (Scheme 12, eq.…”

“…A very elegant and efficient approach to ipsenol ( I ) was communicated by Fukushima et al [64] . via Pd/Et 3 B catalyzed ene‐type reaction of 3‐methylbutanal with isoprene, by using Pd(OAc) 2 (10 mol %), Xantphos (10 mol %), and triethylborane, at rt under a nitrogen atmosphere [64] (Scheme 22).…”

Reconstruction of Carbon Bond Frameworks via Oxapalladacycles Promoted by the Synergistic Effect of Palladium Catalyst and Triethylborane

“…Regarding C-C bond coupling, the ene-type coupling reaction (Prins reaction) can occur in the presence of a Pd catalyst and Xantphos ligand. 9 Et3B promotes the allylation of aldehydes with conjugated dienes to provide homoallyl alcohols. The reaction takes place smoothly at the C-C double bond of the conjugated diene bearing higher electron density through the oxapalladacycle intermediate (Scheme 3).…”

Discussion Addendum for: Nickel‐catalyzed Homoallylation of Aldehydes with 1,3‐Dienes

“…A combination of Pd-catalyst/Xantphos and triethylborane promoted the ene-type reaction of aldehydes and conjugated dienes to afford dienyl homoallyl alcohols in excellent yields (Figure 8). 12 Methyl sorbate underwent formal Baylis-Hillman type C-C bond formation at the -position to provide (2E,4E)-hexadien-1-ol with excellent stereoselectivity. Thus, the combination of transition metal catalyst and triethylborane nicely promoted the coupling reaction of carbonyls and conjugated dienes to furnish the stereodefined bishomoallyl and homoallyl alcohols.…”