活性烯烴和醛在三級胺（如 DABCO = 1,4-Diazabicyclo[2.2.2]octane）的催化下發生的偶聯反應被稱為Baylis-Hillman 反應。膦也可以用于此反應，如果胺或膦是手性的，則發生非對映選擇性的Baylis-Hillman 反應。

堿催化下吸電子基團活化的烯烴和一些親電子化合物（如醛）偶聯得到非常有用的有機合成中間體。當以三級胺作為堿時，特別是以1,4-二氮雜二環[2.2.2]辛烷（ DABCO = 1,4-Diazabicyclo[2.2.2]octane）此反應被稱為Baylis-Hillman反應。1972年Baylis和Hillman首先報道了α，β-不飽和酯，腈，酰胺和酮與各種醛類化合物進行反應。現在用此反應可以合成各種化合物（吸電子基團可以是磺酰基，膦酰基等，親電子化合物也不僅僅是醛）。此反應的一個缺點就是反應速率比較慢，經常需要延長反應時間。現在也發展了好多加快反應速率的方法，如加入膦鹽，加入 Lewis酸，加壓，超聲和微波等方法。

反應機理：

此反應的關鍵步驟是胺催化劑加成到活性烯烴上形成穩定的親核陰離子。此親核陰離子加成到醛上，隨后胺催化劑消除得到產物。

其他的氮親核陰離子也可以參與此反應，如在一些反應中DMAP和DBU比DABCO的效果還好：

對于芳香醛在極性，非極性和質子性溶劑條件下，都確定了反應的速度決定步驟首先是DABCO和丙烯酸酯的加成，而后是和醛的反應。基于反應速率數據，Tyler McQuade 最近提出 (J. Org. Chem. 2005, 70, 3980.DOI)，以下有半縮醛參與反應的機理。

反應實例：

Octanol-Accelerated Baylis-Hillman Reaction
K.-S. Park, J. Kim, H. Choo, Y. Chong, Synlett, 2007, 395-398.

The First One-Pot Synthesis of Morita-Baylis-Hillman Adducts Starting Directly from Alcohols
L. D. S. Yadav, V. P. Srivasta, R. Patel, Synlett, 2010, 1047-1050.

Dramatic Rate Acceleration of the Baylis-Hillman Reaction in Homogeneous Medium in the Presence of Water
J. Cai, Z. Zhou, G. Zhao, C. Tang, Org. Lett., 2002, 4, 4723-4725.

Synthesis of 1,3-Dialkyl-1,2,3-triazolium Ionic Liquids and Their Applications to the Baylis-Hillman Reaction
Y. Jeong, J.-S. Ryu, J. Org. Chem., 2010, 75, 4183-4191.

Sila-Morita-Baylis-Hillman Reaction of Arylvinyl Ketones: Overcoming the Dimerization Problem
A. Trofimov, V. Gevorgyan, Org. Lett., 2009, 11, 253-255.

A Highly Active and Selective Catalyst System for the Baylis-Hillman Reaction
J. You, J. Xu, J. G. Verkade, Angew. Chem. Int. Ed., 2003, 41, 5054-5066.

Traditional Morita-Baylis-Hillman reaction of aldehydes with methyl vinyl ketone co-catalyzed by triphenylphosphine and nitrophenol
M. Shi, Y.-H. Liu, Org. Biomol. Chem., 2006, 4, 1468-1470.

Succesful Baylis Hillman Reaction of Acrylamide with Aromatic Aldehydes
C. Yu, L. Hu, J. Org. Chem., 2002, 67, 219-223.

Ionic Liquid-Immobilized Quinuclidine-Catalyzed Morita-Baylis-Hillman Reactions
X. Mi, S. Luo, J.-P. Cheng, J. Org. Chem., 2005, 70, 2338-2341.

Guanidine-Catalyzed γ-Selective Morita-Baylis-Hillman Reactions on α,γ-Dialkyl-Allenoates: Access to Densely Substituted Heterocycles
P. Selig, A. Turo?kin, W. Raven, Synlett, 2013, 24, 2535-2539.

A Practical Preparation of 2-Hydroxymethyl-2-cyclopenten-1-one by Morita-Baylis-Hillman Reaction
H. Ito, Y. Takenaka, S. Fukunishi, K. Iguchi, Synthesis, 2005, 3035-3038.

Acceleration of the Morita-Baylis-Hillman Reaction by a Simple Mixed Catalyst System
A. Bugarin, B. T. Connell, J. Org. Chem., 2009, 74, 4638-4641.

Asymmetric Morita-Baylis-Hillman Reactions Catalyzed by Chiral Br?nsted Acids
N. T. McDougal, S. E. Schaus, J. Am. Chem. Soc., 2003, 125, 12094-12095.

MgI₂-accelerated enantioselective Morita-Baylis-Hillman reactions of cyclopentenone utilizing a chiral DMAP catalyst
A. Bugarin, B. T. Connell, Chem. Commun., 2010, 46, 2644-2646.

Catalytic Asymmetric Aza-Morita-Baylis-Hillman Reaction of Methyl Acrylate: Role of a Bifunctional La(O-iPr)₃/Linked-BINOL Complex
T. Yukawa, B. Seelig, Y. Xu, H. Morimoto, Y. Xu, H. Morimoto, S. Matsunaga, A. Berkessel, M. Shibasaki, J. Am. Chem. Soc., 2010, 132, 11988-11992.

Chiral Bifunctional Organocatalysts in Asymmetric Aza-Morita-Baylis-Hillman Reactions of Ethyl (Arylimino)acetates with Methyl Vinyl Ketone and Ethyl Vinyl Ketone
M. Shi, G.-N. Ma, J. Gao, J. Org. Chem., 2007, 72, 9779-9781.

A Br?nsted Acid and Lewis Base Organocatalyst for the Aza-Morita-Baylis-Hillman Reaction
K. Matsui, S. Takizawa, H. Sasai, Synlett, 2006, 761-765.

Organocatalytic Tandem Three-Component Reaction of Imine, Alkyl Vinyl Ketone, and Imide via aza-Baylis-Hillman Reaction
S.-e. Syu, Y.-T. Lee, Y.-J. Jang, W. Lin, J. Org. Chem., 2011, 76, 2888-2891.

Organocatalysis of the Morita-Baylis-Hillman Alkylation Using Trialkylphosphines
M. E. Krafft, K. A. Seibert, Synlett, 2006, 3334-3336.

General procedure[Johnson C. L. et al. Tetrahedron Lett. 2004,45 7359]

將苯甲醛（5 mmol）和丙烯酸甲酯（5.5 mmol）添加到含有膦鹽（0.5 mmol）和DBACO（2.5 mmol）的圓底燒瓶中。將燒瓶塞住，在室溫下攪拌24小時。用DCM（10毫升）稀釋混合物，然后用aq連續洗滌。HCl（2M）和水。將有機相干燥濃縮。用快速色譜法（乙酸乙酯/正己烷，1:3）純化殘渣，得到3-羥基-2-甲基亞叉-3-苯基丙酸甲酯。