Table 2.

Passerini reaction on DHMP acids.^a

Entry	DHMP acid	R1	R2	R3	R4	R5	Yield [%]	Product
1	17		H	Et	C6H13	t-Bu	67	19
2	18		H	Bn	C6H13	t-Bu	22	20
3	17		H	Et		cyclohexyl	98	21
4	15	Ph	CH2COOH	Et	iPr	t-Bu	76	22
5	15	Ph	CH2COOH	Et	C10H19	t-Bu	99	23
6	15	Ph	CH2COOH	Et	C7H15	Bn	76	24
7	15	Ph	CH2COOH	Et	C7H15		39	25
8	15	Ph	CH2COOH	Et		C5H11	79	26
9b	–	p-C6H4Fc	CH2COOH	Et	p-C6H4Fc	C5H11	41	27

^aConditions: Room temperature, 3 d in DCM. ^bOne pot procedure: Biginelli acid was not isolated.