S1 Supporting Information The Morita-Baylis-Hillman Reaction of Masked 5-Alkylidene-2- cyclopentenones: A General Entry to 5-Alkylidene-2-(hydroxyalkyl)-2- cyclopentenones Manat Pohmakotr,* Sirinporn Thamapipol, Patoomratana Tuchinda, Palangpon Kongsaeree, Samrarn Prabpai and Vichai Reutrakul* Department of Chemistry, Faculty of Science, Mahidol University, Rama VI Rd., Bangkok 10400, Thailand scmpk@mahidol.ac.th; scvrt@mahidol.ac.th Table of Contents (1) Experimental Section S3 (2) Preparation and spectral data of compound 3a S3 (3) Preparation and spectral data of compound 3b S7 (4) Preparation and spectral data of compound 3c S14 (5) Preparation and spectral data of compound 3d S18 (6) Preparation and spectral data of compound 3e S22 (7) Preparation and spectral data of compound 3f S26 (8) Preparation and spectral data of compound 3g S31 (9) Preparation and spectral data of compound 3h S34 (10) Preparation and spectral data of compound 3i S38 (11) Preparation and spectral data of compound 3j S42 (12) Preparation and spectral data of compound 3k S47 (13) Preparation and spectral data of compound 4a S50 (14) Preparation and spectral data of compound 4b S51 (15) Preparation and spectral data of compound 4c S53 (16) Preparation and spectral data of compound 4d S54 * Corresponding author. Tel.: 66-(0)2-2015158; fax: 66-(0)2-6445126; e-mail: scmpk@mahidol.ac.th, scvrt@mahidol.ac.th