The Diels-Alder Reaction

	M
								R
						R-X
			CHCl3 or PhMe,			-Bu3SnX
							Ph	N CO2Me
				−60-110 C,				95
				0.2−48 h
				39−86%
		SnBu3			SnBu3
	N		1. [4 + 2]					SnBu3
		N				+
		+	2. − N2
	Ph N	CO2Me		Ph	N CO2Me Ph		N	CO2Me
	94				72%		10%
				Br
				S	Br	X	COCl
	RX = HCl, Cl2, Br2, I2, PhI, N		Br,N N,
					, PhCOCl,		(X = O, S)

M

	O			O
	CHNMe2	CHO	Lawesson's reagent	CHO
	+			EtO
			PhH, 0 C-r.t., 56−63%		! "
	EtO O	R		S R
	96			97
	R = H, Ph

M

M

		CHO
CHNMe2			R
O	O	S		S
S	S CHNMe2	S	S	CHO
98	99	100	101
		R = H, Me, Ph

M

M

R2

				R1
				N
				CO2Et
				1,4-dioxane, Rfx, 0.5 h
				27−77%		R2
	R2
	R1					R1
	N			R2		N
	CO2Et		N	R1		CO2Et
+		1,4-dioxane, Rfx,	N	N	1,4-dioxane, Rfx,	+
						R2
	R2
		0.5 h, 30−69%
	R1			CO2Et	0.5 h, 20−69%	R1
	N			102		N
	CO2Et	R1, R2 = H, Me, Ph, CO2Et				CO2Et

	R1	R1	MeCN, r.t., HMOST	S
	O	O
			CoCl2.6H2O, 24 h, 37−64%	H SiR
	H	SiR
				103

R = Me3, Et3, t-BuMe2, PhMe2, Ph2Me

R1 = Me,

R1-R1 = −(CH2)3−

S

H

SiR ! "

M

M

M

						Se
R1	R1	PhMe-Dioxane, 25−100	C	Se		R
O	O + (Me2Al)2Se
		3 h, 18−96%		H R			! "
H	R					Se
	105			104

R

R = Me, i-Pr, C7H15, Ph, Bn

R1 = Me, Et

! "

Se

RCHCl2

+ (Bu3Sn)2Se + 2 Bu4NF.3H2O

R

H

104

Se

R

endo:exo = 80:20 − 14:86

THF, r.t.

R1

3 h,

70−79%

R1

R2

R2

Se

Se

Se

R1, R2 = H, Me

, R = CO2Me

Se

+

THF, r.t., 3 h, 22−71%

R

H R

THF, r.t., 3 h, 24%

R

R1

104

R

R2

R = CO2Me, COMe, PhCO, CN

endo:exo = 80:20

major

M

M M

M

			H	PhSO2SeCl, Et3N, DCM			R
R		N			[R-N=Se]		N
			R1	0 C, 0-20%			Se
					106	107

R = p-XC6H4 (X = Br, Me), o-SMeC6H4, PhO(CH2)2

R1 = H, SMT

N

S Se

M #

		CO2Me			+ TsN=C=O
		CHO
R1						PhMe, Rfx
						36 h
R1								( )n	( )n
				TsN=CHCO2Me
	R							, n = 1, 2	CO2Me
					108
	0-70 C, 3-24 h,							0 C, r.t., 24 h,	N H
R N CO2Me		50-83%				R		57-70%	Ts

Ts

	R, R1	= H, Me,	O
			R = H, Me
	OMe, OSMT

		NHTs
	R	O
		CO2Me

M

M

			O
OR*		N		THF, -100 C to r.t.
	+		N Ph
		N
	R1			12 h, 87-91%
109			O

R1 = n-Pr, Ph, 2-Fu, trans-2-phenylcyclohexyl R* = trans-2-phenylcyclohexyl

R1 O

	N	Ph
	N
R*O	N
+	O	! "
R1 O
	N	Ph
	N
R*O	N

O

M

M M

R*OH R*OCONHOH

110

R* = camphor chiral auxiliary

	O
	R*O N
( )n	O	R1
	111
n = 1, 2	DCM −78 C to r.t., 3 h	R1 = Me, CO2Et
O		O		R1
( )n		R*O	N
R*O
N			O
O
89−93%			65−94%

M

M

M

M

#

M

X	X	OMe	X	OMe
MeO		H		H
	PhH, or neat, 80−150 C	( )n	+	( )n
	6−72 h, 15−88%
( )n		H		H
112		endo		exo
a, n = 1; b, n = 2

	X	112	endo:exo
	W(CO)5	a	98:2
		b	93:7
	O	a	60:40
		b	51:49
W(CO)4PPh		a	94:6
		b	88:12

	M
	X			X OMe	X	OMe
	OMe			H		H
		PhH, or neat, 40−180 C		( )n	+	( )n
	( )n	5−48 h, 75−97%
				H		H
	113			endo		exo
	a, n = 1; b, n = 2
		X	113	endo:exo
		W(CO)5	a	45:55
			b	78:22
		O	a	35:65
			b	49:51

OH		O		O O	O(+)menthyl
	Dess-Martin			O	H
	O(+)menthyl periodinane		O(+)menthyl		OSPDBT
O O	OSPDBT DCM, lutidine	O O	OSPDBT	H	! "
	r.t., 12 h, 79%
114			115	116

O	O			O	O	O O
			O
				O	CO2Et	O O	CO2Et
O	CO2Et
				O		O
O
	PhMe, 200 C, 60 h
O				H	+	H
		BHT, 33%
				O O		O O
O	O
				118a		118b	! "
117	O
	O	O	CO2Me
			OH O
			O	O
			OH
	AcO	H	OH

MeO2C O

119

	M
( )n	( )n
PhO2S	R
R	SO2Ph
	R = H, Me; n = 1, 2
120a	120b

M

O	CO2H	O		O
O	H
		O		O
		H	CO2H	! "
		52%
122		123		121

O	O
	H
	PhH
	H	! "
124	125

Cat.	T ( C)	t (h)	Yield (%)	cis/trans
-	155	5	90	62:38
LiBF4	25	72	100	100:0

M

MeO2C

R1

O

126

R, R1 = H, Me

MeO2C

O

127

O

MeO2C

128

O

CO2Me

129

280−290 C

63−90%

280 C

100%

290 C

97%

280 C

83%

MeO2C R	MeO2C R
H	H
	+
O	O
H	H

MeO2C

H

O

H

H

O

H

MeO2C

	H	H
		+
	O	O
	H
		H
	MeO2C
		MeO2C
	40%	60%

M

M

OTBDPS

		O
O	O	+ O O	PhMe, 120 C
			20 h, BHT, 65−70%
		t-Bu
		131

Me3SiO OMOM

130

CO2H

Me

O

RO O

O O

OTBDPS

O

O

O

O O

Me

Me3SiO OMOM

132

OTBDPS

O O

Me

Me3SiO OMOM

133

Me

OMOM

(-)-chlorothricolide