P(PhCH2NCH2CH2)3N: An Efficient Lewis Base Catalyst for the Synthesis of Propargylic Alcohols and Morita−Baylis−Hillman Adducts via Aldehyde Alkynylation
摘要:
Proazaphosphatrane P(PhCH2NCH2CH2)(3)N (1a) is an efficient catalyst for the addition of aryl trimethylsilyl alkynes to a variety of aromatic, aliphatic, and heterocyclic aldehydes in THF at room temperature. The reaction conditions are mild and employ a low catalyst loading (ca. 5 mol %). Only propargylic alcohols were isolated in good to excellent isolated yields when electron-rich, electron-neutral, heterocyclic, and aliphatic aldehydes were employed, whereas beta-branched Morita-Baylis-Hillman (MBH) type adducts were isolated with electron-deficient aromatic aldehydes after conventional acid hydrolysis of the TMS ether products. Alkynes containing heterocyclic and aromatic groups bearing electron-withdrawing or -donating substituents underwent clean addition to cyclohexanecarboxaldehyde and to electron-rich aromatic aldehydes to give propargylic alcohols in excellent isolated yields. beta-Branched Morita-Baylis-Hillman (MBH) type adducts were isolated when electron-deficient aromatic aldehydes were employed. Reaction pathways to both types of products are proposed.
Access to 6H-naphtho[2,3-c]chromenes by a palladium-catalyzed reaction of 2-haloaryl allene with 2-alkynylphenol
作者:Xiaolin Pan、Mo Chen、Liangqing Yao、Jie Wu
DOI:10.1039/c4cc00374h
日期:——
A palladium-catalyzed reaction of 2-haloaryl allene with 2-alkynylphenol is described, leading to 6H-naphtho[2,3-c]chromenes in good to excellent yields. This transformation proceeds efficiently with excellent chemoselectivity and regioselectivity.
P(PhCH<sub>2</sub>NCH<sub>2</sub>CH<sub>2</sub>)<sub>3</sub>N: An Efficient Lewis Base Catalyst for the Synthesis of Propargylic Alcohols and Morita−Baylis−Hillman Adducts via Aldehyde Alkynylation
作者:Kuldeep Wadhwa、Venkat Reddy Chintareddy、John G. Verkade
DOI:10.1021/jo9012332
日期:2009.9.4
Proazaphosphatrane P(PhCH2NCH2CH2)(3)N (1a) is an efficient catalyst for the addition of aryl trimethylsilyl alkynes to a variety of aromatic, aliphatic, and heterocyclic aldehydes in THF at room temperature. The reaction conditions are mild and employ a low catalyst loading (ca. 5 mol %). Only propargylic alcohols were isolated in good to excellent isolated yields when electron-rich, electron-neutral, heterocyclic, and aliphatic aldehydes were employed, whereas beta-branched Morita-Baylis-Hillman (MBH) type adducts were isolated with electron-deficient aromatic aldehydes after conventional acid hydrolysis of the TMS ether products. Alkynes containing heterocyclic and aromatic groups bearing electron-withdrawing or -donating substituents underwent clean addition to cyclohexanecarboxaldehyde and to electron-rich aromatic aldehydes to give propargylic alcohols in excellent isolated yields. beta-Branched Morita-Baylis-Hillman (MBH) type adducts were isolated when electron-deficient aromatic aldehydes were employed. Reaction pathways to both types of products are proposed.