A regioselective formal [4+2] cycloaddition reaction of nitrostyrene derived MBH alcohol and 2‐arylidene‐1,3‐indanedione resulted in functionalized tetrahydrospiropyran derivatives with excellent chemical yields (up to 93 %). The reaction tolerated various electron rich and electron deficient substituents on the aryl group of 2‐arylidene‐1,3‐indanedione as well as MBH alcohol. The utility of MBH alcohol as an ambident substrate, which is performing the dual role of nucleophile and electrophile with 2‐arylidene‐1,3‐indanediones was successfully demonstrated for 20 derivatives. A single isomer was obtained exclusively in all the products via cascade process which followed an oxa‐Michael–Michael addition sequence using cesium carbonate as base. Control experiments were carried out to understand the mechanistic details of the reaction. These experiments prove that the reaction undergoes a stepwise pathway rather than a concerted mechanism.

Dedicated to Prof. Kwunmin ChenA sequential formal [4 + 2] cyclization involving cascade protocol has been developed for the construction of multisubstituted six-membered spirocyclic scaffolds by using 2arylidene-1, 3-indanedione and nitro allylic alcohol. This method generates four stereocenters in spiropyran ring with high diastereoselctivity (99 : 1) under mild reaction conditions.

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A [3+2] annulation protocol for the construction of functionalized spirocyclopentenes utilizing 1,3-indanedione derived benzylidene-1,3-indanedione and ethyl-2,3-butadienoate at room temperature was developed.

A simple and efficient cascade reactionviaformal [1+2+3] cyclization of 1,3‐indanedione, aldehyde and 2‐naphthol is reported using K2CO3as a base. The advantage includes metal‐free conditions, varied substrate scope and shortened reaction duration with high diastereoselectivity (i. e., 99 : 1) resulting in the formation of two carbon‐carbon as well as two carbon‐oxygen bonds through Knoevenagel‐Friedel‐Crafts‐Hemiketalization sequence resulting in three contiguous stereocenters.

The reaction of β‐naphthol with nitrostyrene derived primary MBH acetates in presence of Cs2CO3 as base resulted in the formation of 3‐nitro‐4‐phenyl‐3,4‐dihydro‐2H‐naphthopyran as the major isomer via SN2′ process. Due to the bis‐electrophilic nature of MBH acetates, the minor product 3‐nitro‐2‐phenyl‐3,4‐dihydro‐2H‐naphthopyran was also obtained presumably due to SN2 process with γ ‐attack on MBH acetates. The state of the art density functional theory (DFT) calculations were carried out to account for these competitive pathways towards the formation of major and minor products.

A simple and convenient protocol has been demonstrated for the construction of spiro[chroman‐3,2′‐indanedione] via Oxa‐Michael/Michael cascade reaction sequence using 2‐arylidene‐1,3‐indanedione and (E)‐2‐(2‐nitrovinyl)phenol. This [4+2] cyclisation protocol results in the generation of two stereocentres along with an all carbon quaternary centre in good to high chemical yields of upto 93 %. A triple cascade reaction approach was carried out for the construction of spiro[chroman‐3,2′‐indanedione] using [1+1+4] cyclisation protocol.